[CI] Support centralize version bump pipeline

The release team wants to be able to trigger and coordinate version-bump automation across all relevant components, including Cloudbeat. Their plan is to add a Buildkite pipeline in each repo that will handle this automation.

After our meeting with @jmlrt, one of the proposed actions is that the BK pipeline will trigger our existing version-bump [GitHub Action](https://github.com/elastic/cloudbeat/blob/main/.github/workflows/bump-version.yml), which today is triggered manually.
Note that this action covers major and minor releases, while patch releases are currently handled by a [bot](https://github.com/elastic/ingest-dev/blob/28e2593b8d46a466028ad8f607063f13d55f588d/release_scripts/cloudbeat.mak#L108) maintained by the ingest team.

It might be worth retiring the patch-release bot and moving to a single, unified flow for version bumps.
To support that, we could update our GitHub Action so it can handle patch bumps without creating the integration PRs.

Relevant links:
- [Slack discussion](https://elastic.slack.com/archives/C0348SPA1RN/p1763397789889289)
- [PSI](https://docs.google.com/document/d/1VxKftPLqC3EtkxtjWpkbHqfP0Oen9142Piri-yviTVw/edit?tab=t.0#heading=h.bwbdq2a7jpcy)