ci: run docs builds on Namespace (#38921)

.github/workflows/docs.yaml

@@ -23,7 +23,12 @@ env:
 jobs:
   docs:
     name: build docs
-    runs-on: ubuntu-24.04
+    runs-on: ${{
+      (github.repository == 'commaai/openpilot') &&
+      ((github.event_name != 'pull_request') ||
+      (github.event.pull_request.head.repo.full_name == 'commaai/openpilot'))
+      && fromJSON('["namespace-profile-amd64-8x16"]')
+      || fromJSON('["ubuntu-24.04"]') }}
     steps:
     - uses: commaai/timeout@v1
     - uses: actions/checkout@v7