[8.17] (backport #18016) Start observabilitySRE container builds immediately on DRA

[mergify]

Previously as the pipeline for publishing observabilitySRE artifacts was being developed that part of the pipeline only executed after the rest of the DRA artifacts had been prepared. This sacrificed build time for ensuring that failures did not disrupt the rest of the DRA process. Now that the workflow has been stabilized it is no longer necessary to wait. This commit removes the deps for the DRA build to complete before starting the observabilitySRE artifact creation. This should decrease the total time for the DRA pipeline to complete.

---

This is an automatic backport of pull request #18016 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e676b59 has failed:

On branch mergify/bp/8.17/pr-18016
Your branch is up to date with 'origin/8.17'.

You are currently cherry-picking commit e676b59a.
  (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 <file>..." to mark resolution)
	both modified:   .buildkite/scripts/dra/generatesteps.py

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

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarQube

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 15e63b2

Failed CI Steps

• 🥼 IT Persistent Queues / part 1-of-6
• 🥼 IT Persistent Queues / part 4-of-6

cc @donoghuc