Remove .pytool CodeQL fallback in the CodeQL workflow

[makubacki]

PR #299 updated .sync/workflows/leaf/codeql.yml to first check the new location (as of Mu 2311) for the CodeQL plugin in Mu Basecore BaseTools. If not found, it falls back to the previous location in .pytools.

This is to allow immediate backward compatibility with the latest Mu DevOps release across existing Mu branches. It is recommended that 2302 (and other relevant branches) move to the BaseTools location. When all branches are confirmed to have moved, the fallback to .pytools can be removed in the file.