feat(store): update does not wipe out labels (backport of #10335)

[kumahq]

Automatic cherry-pick of #10335 for branch release-2.5

Generated by action

cherry-picked commit b0abc25
⚠️ ⚠️ ⚠️ Conflicts happened when cherry-picking! ⚠️ ⚠️ ⚠️

On branch release-2.5
Your branch is up to date with 'origin/release-2.5'.

You are currently cherry-picking commit b0abc25a4.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   pkg/core/resources/apis/meshservice/vip/allocator.go
	both modified:   pkg/core/resources/store/options.go
	both modified:   pkg/plugins/resources/k8s/store.go
	both modified:   pkg/plugins/resources/memory/store.go
	both modified:   pkg/plugins/resources/postgres/pgx_store.go
	both modified:   pkg/test/store/store_test_template.go

no changes added to commit (use "git add" and/or "git commit -a")