workflows/artifacts.yml: do not upload build artifacts for branches

.github/workflows/artifacts.yml

@@ -27,11 +27,9 @@ jobs:
           path: server/dist
       - name: cd/Upload artifacts to S3
         env:
-          BRANCH_NAME: ${{ github.event.workflow_run.head_branch }}
           REPO_NAME: ${{ github.event.repository.name }}
           COMMIT_SHA: ${{ github.event.workflow_run.head_sha }}
         run: |
-          aws s3 cp server/dist/ s3://pr-builds.mattermost.com/$REPO_NAME/$BRANCH_NAME/ --acl public-read --cache-control "no-cache" --recursive --no-progress
           aws s3 cp server/dist/ s3://pr-builds.mattermost.com/$REPO_NAME/commit/$COMMIT_SHA/ --acl public-read --cache-control "no-cache" --recursive --no-progress
 
   build-docker: