Adds CI to error on unnecessary variable modification (#29861)

* begin the burndown? (y/n)

* okay update requirements?

* change the error name

* there we go

* tweak

* first bit of the burndown

* more

* burndown complete

* return the exit code!

* review

* Revert "first bit of the burndown"

This reverts commit 34155bd991.

* fix

* fixes

* last fix

* remove deprecated avulto stuff

.github/workflows/ci.yml

@@ -48,6 +48,7 @@ jobs:
           python tools/ci/unticked_files.py ${GITHUB_WORKSPACE}
           python tools/ci/illegal_dme_files.py ${GITHUB_WORKSPACE}
           python tools/ci/define_sanity.py
+          python tools/ci/identical_variables.py
           python tools/ci/restrict_file_types.py
           python tools/ci/verify_sql_version.py
           python tools/ci/no_duplicate_definitions.py