Revert "GH Actions: Bypass PEP 668 in runners (#8020)" (#8033)

.github/workflows/codeowner-self-approval.yml

@@ -13,7 +13,7 @@ permissions:
 
 jobs:
   approve:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     # Only run if the PR author enabled auto-merge, not someone else.
     # Also run if a new approval was created, as this affects whether we can
     # auto-approve. There is a risk of infinite loops here, though -- when we
@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Install dependencies
-        run: pip install --break-system-packages codeowners PyGithub
+        run: pip install codeowners PyGithub
 
       # Approve the PR, if the author is only editing files owned by themselves.
       - name: Auto-approve PR if permitted