fix: revert to ubuntu-latest action

Author: RomneyDa

.github/workflows/pr-checks.yaml

@@ -361,7 +361,7 @@ jobs:
           is_fork: ${{ github.event.pull_request.head.repo.fork == true || github.actor == 'dependabot[bot]' }}
 
   jetbrains-tests:
-    runs-on: ubuntu-latest-8-cores
+    runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
       - name: Free disk space