Don't install 'ninja' for MacOS CI builds

Not needed, it's already included in the environment

Author: rollbear

.github/workflows/ci.yml

@@ -1787,7 +1787,7 @@ jobs:
         if: startsWith(matrix.config.os, 'macos')
         shell: bash
         run: |
-          env brew install parallel ninja
+          env brew install parallel
           echo "CC=clang" >> $GITHUB_ENV
           echo "CXX=clang++" >> $GITHUB_ENV