fix(deployment): remove deployment.labels from selector.matchLabels (#1011)

This PR removes the inclusion of `deployment.labels` in the Deployment's `selector.matchLabels` field.

## Changes
- Removed the conditional block that adds `deployment.labels` to `selector.matchLabels`
- This ensures the selector remains immutable and only contains pod-identifying labels

Reviewed-on: https://gitea.com/gitea/helm-gitea/pulls/1011
Reviewed-by: Markus Pesch <volker.raschek@noreply.gitea.com>
Co-authored-by: Tarun Gaba <tarun.gaba7@gmail.com>
Co-committed-by: Tarun Gaba <tarun.gaba7@gmail.com>

templates/gitea/deployment.yaml

@@ -24,9 +24,6 @@ spec:
   selector:
     matchLabels:
       {{- include "gitea.selectorLabels" . | nindent 6 }}
-      {{- if .Values.deployment.labels }}
-      {{- toYaml .Values.deployment.labels | nindent 6 }}
-      {{- end }}
   template:
     metadata:
       annotations: