feat: delete labels using regex

[karan2704]

What this PR does / why we need it:
Uses regex in dropLabel confg to drop labels following a defined pattern

Which issue(s) this PR fixes:
Fixes #17078

Special notes for your reviewer:

Checklist

• [✔️] Reviewed the CONTRIBUTING.md guide (required)
• [✔️] Documentation added
• [✔️] Tests updated
• [✔️] Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• [✔️] Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• [✔️] If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[karan2704]

Hi @JStickler , could you please review this change or tag someone else who might?