Ensure CI can run on forked repo PRs

Put the runner env variable in the workflow directly instead of GH project
config as it’s not available to the forked repositories otherwise when
submitting PRs: https://github.com/orgs/community/discussions/44322.

.github/workflows/qa.yaml

@@ -12,11 +12,14 @@ env:
     ca-certificates curl dconf-cli gcc gettext git libnss-wrapper libsmbclient-dev
     libkrb5-dev libwbclient-dev pkg-config python3-coverage samba sudo
     libglib2.0-dev gvfs libpam0g-dev
+  # Put the runner env variable here instead of GH project config as it’s not available to the forked repositories
+  # otherwise when submitting PRs: https://github.com/orgs/community/discussions/44322.
+  RUNNER: ubuntu-24.04
 
 jobs:
   sanity:
     name: Code sanity
-    runs-on: ${{ vars.RUNNER }}
+    runs-on: ${{ env.RUNNER }}
     steps:
       - name: Install dependencies
         run: |