feat(admission-controller): Add labels to VAC webhook to adopt existing one

[airadier]

What this PR does / why we need it:

A recent change in the chart prevents the AC from installing if it was an upgrade from a previous version. The reason is that the old chart didn't treat the VAC registration as part of the lifecycle, and now we are doing.

To fix this, now we skip creating the resource as part of the lifecycle in case it already exists but doesn't contain the right annotations to be adopted. In the post-install hook we set the right annotations, so next upgrade or install, it will be adopted as part of the lifecycle and managed correct.

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• Title of the PR starts with type and scope, (e.g. feat(agent,node-analyzer,sysdig-deploy):)
• Chart Version bumped for the respective charts
• Variables are documented in the README.md (or README.tpl in some charts)
• Check GithubAction checks (like lint) to avoid merge-check stoppers
• All test files are added in the tests folder of their respective chart and have a "_test" suffix

Check Contribution guidelines in README.md for more insight.