test: Experimentally changed TEST_PROBE_ONLY to not cover 2.x

Author: cure53

.github/workflows/build-and-test.yml

@@ -40,6 +40,6 @@ jobs:
           run: npm run test:ci
         env:
           TEST_BROWSERSTACK: ${{ startsWith(matrix.node-version, '21') }}
-          TEST_PROBE_ONLY: ${{ github.ref != 'refs/heads/main' }}
+          TEST_PROBE_ONLY: ${{ github.ref != 'refs/heads/main' && github.ref != 'refs/heads/2.x' }}
           BS_USERNAME: ${{ secrets.BS_USERNAME }}
           BS_ACCESSKEY: ${{ secrets.BS_ACCESSKEY }}