Only one preview url is generated for multisite

With 2 workflow.yml files, each one meant to deploy to a hosting channel for a site on a firebase project, only one comment post with deploy preview url is possible on the pull_request. Also, the preview url of the workflow that finishes last overwrites that posted by the first one.

```yaml
# workflow 1
- uses: FirebaseExtended/action-hosting-deploy@v0
with:
repoToken: '${{ secrets.GITHUB_TOKEN }}'
firebaseServiceAccount: '${{ secrets.FIREBASE_SERVICE_ACCOUNT }}'
projectId: '${{ secrets.PROJECT_ID }}'
channelId: '${{ gitHub.sha }}-c1'
target: TARGET_NAME_1
```

```yaml
# workflow 2
- uses: FirebaseExtended/action-hosting-deploy@v0
with:
repoToken: '${{ secrets.GITHUB_TOKEN }}'
firebaseServiceAccount: '${{ secrets.FIREBASE_SERVICE_ACCOUNT }}'
projectId: '${{ secrets.PROJECT_ID }}'
channelId: '${{ gitHub.sha }}-c2'
target: TARGET_NAME_2
```

Start by reproducing the issue with the two workflow.yml examples and inspect how the action creates or updates pull-request comments. Confirm that both hosting preview URLs are retained instead of one overwriting the other; the issue does not name specific source files or tests.

Written by the indexing model from the issue text.