Revert "Try something simpler for CI fix"

This reverts commit 3e7bb8a.

Author: WardBrian

.github/workflows/main.yml

@@ -110,7 +110,8 @@ jobs:
         run: |
           install_cmdstan -h
           install_cxx_toolchain -h
-          python -m cmdstanpy.install_cmdstan --compiler --version ${{ needs.get-cmdstan-version.outputs.version }} --cores 2
+          $env:TBB_CXXFLAGS = "-D_UCRT"
+          python -m cmdstanpy.install_cmdstan --version ${{ needs.get-cmdstan-version.outputs.version }} --cores 2
           echo "TBB_CXXFLAGS+=-D_UCRT" >> ~/.cmdstan/cmdstan-${{ needs.get-cmdstan-version.outputs.version }}/make/local
 
       - name: Run tests