CI: remove tmate used for debugging

Also remove dead code selecting pip version

.github/workflows/test.yml

@@ -148,9 +148,6 @@ jobs:
     - name: make fish_run_tests
       run: |
         make -C build VERBOSE=1 fish_run_tests
-    - name: Setup tmate session
-      if: ${{ failure() }}
-      uses: mxschmitt/action-tmate@v3
 
   windows:
     runs-on: windows-latest