Different release-please configs in same repository and release from brach

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**- What you're trying to do**
Configure multiple relsease please configs in same github repo using same branch (master) as target

**- What code you've already tried**

two base paths in repo (backend/cloud and backend/edge) with different configs and manifest

```
- uses: googleapis/release-please-action@main # googleapis/release-please-action@v4
id: release
with:
token: ${{ secrets.GITHUB_TOKEN }}
config-file: backend/edge/release-please-config-backend-edge.json
manifest-file: backend/edge/release-please-manifest-backend-edge.json
```
```
- uses: googleapis/release-please-action@main # googleapis/release-please-action@v4
id: release
with:
token: ${{ secrets.GITHUB_TOKEN }}
config-file: backend/cloud/release-please-config-backend-edge.json
manifest-file: backend/cloud/release-please-manifest-backend-edge.json
```

**- Any error messages you're getting**

Release PR are being overriden when action is triggered as both configuration uses the same branch `release-please--branches--master`. Would it be possible to use different configs with diferent PR branches but keeping same target branch?

Review the two workflow steps and the backend/edge and backend/cloud release-please configuration and manifest files first. Check how release-please derives release PR branches when both configurations target master; done would be a documented supported configuration or a confirmed limitation with clear guidance.

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