Fix xvfb-run usage error in Linux browser tests

- Ensured the xvfb-run command is on a single line to prevent bash interpretation errors from missing line continuations.

Author: Awallky

.github/actions/linux_browser_tests/action.yaml

@@ -58,11 +58,8 @@ runs:
 
         # Wrap the execution in xvfb-run for virtual display.
         # We pass --gtest_output to the runner script, which we should ensure it handles.
-        xvfb-run -a --server-args="${XVFB_SERVER_ARGS}"
-            python3 "${RUN_BROWSER_TESTS_PY}" "${RUNNER_BINARY}"
-            --gtest_filter="${TEST_FILTER}"
-            --gtest_output="xml:${GITHUB_WORKSPACE}/results/cobalt_browsertests_result.xml"
-            2>&1 | tee "${GITHUB_WORKSPACE}/results/cobalt_browsertests_log.txt"
+        # Note: Using a single line to avoid backslash continuation issues in GitHub Actions.
+        xvfb-run -a --server-args="${XVFB_SERVER_ARGS}" python3 "${RUN_BROWSER_TESTS_PY}" "${RUNNER_BINARY}" --gtest_filter="${TEST_FILTER}" --gtest_output="xml:${GITHUB_WORKSPACE}/results/cobalt_browsertests_result.xml" 2>&1 | tee "${GITHUB_WORKSPACE}/results/cobalt_browsertests_log.txt"
 
     - name: Archive Browser Test Results
       if: always()