disable the Clang format check job

Needs some more work to reformat everything, before this can be enabled.

.github/workflows/build_and_test.yml

@@ -12,6 +12,9 @@ jobs:
   check_code_format:
     name: Check code formatting
     runs-on: 'ubuntu-20.04'
+    # The code currently doesn't pass formatting.
+    # Enable this workflow job once it does, to detect regressions.
+    if: false
     steps:
       - uses: actions/checkout@v4
       - name: Check clang-format (make test-formatting)