[8.15](backport #40633) updatecli: bump ironbank UBI

[mergify]

What does this PR do?

Enable updatecli policies to bump the Ironbank versions automatically, then #39988 and #40469 won't be manually created.

Those policies can be found at https://github.com/elastic/oblt-updatecli-policies/tree/main/updatecli/policies/ (NOTE: This is a private repository only accessible by Elastic employees)

Additional changes

• Refactor the updatecli pipelines to use the values.d/scm.yml file.
• Change files to a different location

Why is it important?

One less thing to be worried about.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

How to test this PR locally

1. gh pr checkout 40633
2. Install updatecli
3. Diff (dry-run)

$ GITHUB_TOKEN=$(gh auth token) updatecli compose diff --experimental

4. Create Pull Request if new changes

$ GITHUB_REPOSITORY=elastic/beats \
   GITHUB_ACTOR=v1v \
   GITHUB_TOKEN=$(gh auth token) \
updatecli compose apply --experimental

Related issues

See elastic/apm-server#13934

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

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This is an automatic backport of pull request #40633 done by [Mergify](https://mergify.com).

[botelastic]

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