Raise per-test timeout for playwright-a11y to 60s (#61091)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: heiskr

.github/workflows/headless-tests.yml

@@ -59,6 +59,7 @@ jobs:
           PLAYWRIGHT_WORKERS: ${{ fromJSON('[1, 4]')[github.repository == 'github/docs-internal'] }}
           # workaround for https://github.com/nodejs/node/issues/59364 as of 22.18.0
           NODE_OPTIONS: '--no-experimental-strip-types'
+          PLAYWRIGHT_TIMEOUT: ${{ matrix.node == 'playwright-a11y' && '60000' || '' }}
 
         # Run playwright rendering tests and a11y tests (axe scans) as distinct checks
         # so that we can run them without blocking merges until we can be confident