CI: Revert OneLoc syntax to last working

[zivkan]

Bug

Fixes: Infrastructure

Description

Looking at the docs on OneLoc: https://github.com/dotnet/arcade/blob/main/Documentation/OneLocBuild.md#if-youre-releasing-from-a-branch-other-than-main-including-servicing-branches

It seems to me that the normal workflow is we only run OneLoc on the main (dev) branch, not release branches.

So, revert the OneLoc CI yaml to what last worked, and if we start getting loc updates from release branches, we'll deal with it when it happens, possibly by hardcoding the branch name in the release branch itself.

PR Checklist

• Meaningful title, helpful description and a linked NuGet/Home issue
• Added tests N/A
• Link to an issue or pull request to update docs if this PR changes settings, environment variables, new feature, etc. N/A

[dotnet-policy-service]

Since this PR is changing CI as it modifies YML files, please verify that you've addressed how this change should apply to release branches. Either:

• Link to equivalent PRs or Issues for each currently supported branch.
  or
• Explain in the PR description why this change doesn't apply to release branches.

[zivkan]

superseded by #6859