test: align the file names of the helm unit tests with the chart conventions

The chart conventions demand camelCase file names, forbid short names like `svc` and require the unit tests to
mirror the template structure. The unit tests followed none of that consistently. Four casings existed side by
side - camelCase (extraInitContainers.yaml), kebab-case (checksum-annotations.yaml), a snake and kebab mix
(init_directory_structure.sh-rootless.yaml) and all caps (HA.yaml) - so there was no pattern to copy when
adding a suite, which is how the inconsistency kept growing.

Three groups of problems are fixed:

- svc-configuration.yaml used exactly the short name the conventions forbid for files and keys.
- Several file names repeated their own directory, for example deployment/deployment-additional-config.yaml and
  metric-secret/metrics-secret-servicemonitor-disabled.yaml, which names the subject three times. The directory
  already carries that information, so the file name now only carries the scenario. The default scenario of a
  template is named basics.yaml.
- Four suites lived in a directory of a template they do not assert on. They were filed under deployment/
  because the deployment is rendered as a side effect, not because it is the subject:

      deployment/deprecations.yaml                -> deprecation/deployment.yaml
      deployment/inline-config.yaml               -> config/inlineConfig.yaml
      deployment/storage-class-configuration.yaml -> persistentVolumeClaim/storageClass.yaml
      deployment/svc-configuration.yaml           -> service/configuration.yaml

  storage-class-configuration.yaml is the clearest case: a persistentVolumeClaim directory already existed next
  to it. The suite titles of the two suites whose subject changed are adjusted accordingly.

The Makefile passed `--file unittests/helm/values-conflicting-checks.yaml`, but that file does not exist in the
tree. `helm unittest` ignores a missing path without a warning, so the flag has been dead for an unknown amount
of time while still suggesting the checks run. It is removed; the `unittests/helm/**/*.yaml` glob would pick
the file up anyway if it ever returns.

The naming rule is written down in the copilot instructions, together with the constraint that the glob matches
only a single directory level, so a suite can never be placed directly in unittests/helm/.

All 49 suites and 267 tests still pass.

Co-authored-by: Copilot <copilot@github.com>

unittests/helm/serviceAccount/basics.yaml

@@ -0,0 +1,102 @@
+chart:
+  appVersion: 1.27.3 # renovate: datasource=docker registryUrl=https://docker.gitea.com depName=gitea
+release:
+  name: gitea-unittests
+  namespace: testing
+suite: Test serviceAccount
+templates:
+  - templates/serviceAccount.yaml
+tests:
+  - it: Render the ServiceAccount by default
+    asserts:
+      - hasDocuments:
+          count: 1
+      - containsDocument:
+          kind: ServiceAccount
+          apiVersion: v1
+          name: gitea-unittests
+          namespace: testing
+      - notExists:
+          path: metadata.annotations
+      - equal:
+          path: metadata.labels
+          value:
+            app: gitea
+            app.kubernetes.io/instance: gitea-unittests
+            app.kubernetes.io/managed-by: Helm
+            app.kubernetes.io/name: gitea
+            app.kubernetes.io/version: 1.27.3 # renovate: datasource=docker registryUrl=https://docker.gitea.com depName=gitea
+            helm.sh/chart: gitea-0.0.0
+            version: 1.27.3 # renovate: datasource=docker registryUrl=https://docker.gitea.com depName=gitea
+      - equal:
+          path: automountServiceAccountToken
+          value: false
+      - notExists:
+          path: imagePullSecrets
+
+  - it: Skip rendering when serviceAccount.enabled is false
+    set:
+      serviceAccount:
+        enabled: false
+    asserts:
+      - hasDocuments:
+          count: 0
+
+  - it: Skip rendering when an existing ServiceAccount is used
+    set:
+      serviceAccount:
+        existingServiceAccount:
+          enabled: true
+          existingServiceAccountName: externally-existing-serviceaccount
+    asserts:
+      - hasDocuments:
+          count: 0
+
+  - it: Add custom labels when serviceAccount.new.labels is defined
+    set:
+      serviceAccount:
+        new:
+          labels:
+            custom: label
+    asserts:
+      - equal:
+          path: metadata.labels.custom
+          value: label
+
+  - it: Add custom annotations when serviceAccount.new.annotations is defined
+    set:
+      serviceAccount:
+        new:
+          annotations:
+            myCustom: annotation
+    asserts:
+      - equal:
+          path: metadata.annotations.myCustom
+          value: annotation
+
+  - it: Mount the token when serviceAccount.new.automountServiceAccountToken is true
+    set:
+      serviceAccount:
+        new:
+          automountServiceAccountToken: true
+    asserts:
+      - equal:
+          path: automountServiceAccountToken
+          value: true
+
+  - it: Reference image pull secrets when serviceAccount.new.imagePullSecrets is defined
+    set:
+      serviceAccount:
+        new:
+          imagePullSecrets:
+            - name: testing-image-pull-secret
+            - name: another-pull-secret
+    asserts:
+      - contains:
+          path: imagePullSecrets
+          content:
+            name: testing-image-pull-secret
+      - contains:
+          path: imagePullSecrets
+          content:
+            name: another-pull-secret