Avoid duplicate CI runs when starting a PR from upstream branch (#2788)

.github/workflows/pull_request.yml

@@ -1,6 +1,12 @@
 name: Build and Test
 
-on: [pull_request, push]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+      # For testing CI without starting a pull request:
+      - test/*
 
 permissions:
   contents: read
@@ -14,10 +20,10 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v5
-      - uses: ./.github/actions/setup-linux
       - uses: pre-commit/[email protected]
 
   linux_build_and_test:
+    needs: check_lint
     strategy:
       matrix:
         runner:
@@ -75,6 +81,7 @@ jobs:
 
   linux_fedora_build_cpp:
     name: Linux Fedora CPP Build (${{ matrix.arch }})
+    needs: check_lint
     strategy:
       fail-fast: false
       matrix: