Disable OneLocBuild PRs against non-main branches

[Copilot]

The OneLocBuild pipeline was opening localization PRs against both main and active vs* release branches. Loc PRs should only target main.

Context

.vsts-dotnet.yml has two OneLocBuild jobs in the localization stage — one for vs* release branches (gated by EnableReleaseOneLocBuild) and one for main. The release-branch job was enabled, causing unwanted loc PRs against servicing branches.

Changes Made

• EnableReleaseOneLocBuild now defaults to false and is conditionally overridden to true only when on the main branch, following the same conditional variable pattern used elsewhere in the file.

This variable is evaluated at template compilation time (condition: ${{ variables.EnableReleaseOneLocBuild }}), so on vs* branches the variable resolves to false and the release-branch OneLocBuild job is suppressed entirely. The main branch job is unaffected.

Testing

CI pipeline configuration change only — no code changes.

Notes

The EnableReleaseOneLocBuild toggle already existed for this purpose; this PR makes its value branch-conditional rather than a static override.

[dotnet-policy-service]

Hello @copilot, I noticed that you’re changing an .swr file or any file under src/Package/MSBuild.VSSetup.. Please make sure to validate this change by an experimental VS insertion. This is accomplished by pushing to an exp/* branch, which requires write permissions to this repo.

[JanProvaznik]

@copilot variable should have value based on if we're on the main branch

[Copilot]

@copilot variable should have value based on if we're on the main branch

Updated in 77d7347 — EnableReleaseOneLocBuild now defaults to false and is conditionally overridden to true only on main, following the same pattern used for SourceBranch in the file.

[JanProvaznik]

@OvesN ptal and merge

[Copilot]

Pull request overview

Disables OneLocBuild loc PRs against vs* release branches by defaulting EnableReleaseOneLocBuild to false, only overriding to true on main (where the release-branch job isn't instantiated anyway, so the override is effectively a no-op but follows the existing conditional-variable pattern used elsewhere in the file).

Changes:

• Default EnableReleaseOneLocBuild to false so the vs*-gated OneLocBuild job's condition evaluates false on release branches.
• Add a ${{ if eq(Build.SourceBranch, 'refs/heads/main') }} block overriding it to true (matches surrounding style; has no functional effect since the release-branch loc job is itself gated on refs/heads/vs).