Change job/pod role bindings rendering & refactor related tests

[Miretpl]

Mainly simplifies the rendering logic for job and pod launcher role bindings by removing loops. Other changes are:

1. Adding a condition on the scheduler.enabled flag for scheduler SA-related bindings
2. Refactors job/pod/scc rolebindings-related tests for better readability

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[jscheffl]

This is also 1.2x compatible, backport to maintenance branch? Or only keeping this on main?

[Miretpl]

Also for 1.2x. There shouldn't be any issue with backport, but if there will be some, I will create a separate PR

[jscheffl]

Args, setting the label too late :-(

[github-actions]

Backport failed to create: chart/v1-2x-test. View the failure log Run details

Note: As of Merging PRs targeted for Airflow 3.X
the committer who merges the PR is responsible for backporting the PRs that are bug fixes (generally speaking) to the maintenance branches.

In matter of doubt please ask in #release-management Slack channel.

Status	Branch	Result
❌	chart/v1-2x-test

You can attempt to backport this manually by running:

cherry_picker 00400a5 chart/v1-2x-test

This should apply the commit to the chart/v1-2x-test branch and leave the commit in conflict state marking
the files that need manual conflict resolution.

After you have resolved the conflicts, you can continue the backport process by running:

cherry_picker --continue

If you don't have cherry-picker installed, see the installation guide.

[jscheffl]

@Miretpl Can you back-port?

[Miretpl]

@jscheffl backport ready #66634