Use pytest CLI directly instead of via Python module

This prevents the current directory from being added to the search path.

Author: maresb

.github/workflows/test.yml

@@ -176,7 +176,7 @@ jobs:
           if [[ $FAST_COMPILE == "1" ]]; then export PYTENSOR_FLAGS=$PYTENSOR_FLAGS,mode=FAST_COMPILE; fi
           if [[ $FLOAT32 == "1" ]]; then export PYTENSOR_FLAGS=$PYTENSOR_FLAGS,floatX=float32; fi
           export PYTENSOR_FLAGS=$PYTENSOR_FLAGS,warn__ignore_bug_before=all,on_opt_error=raise,on_shape_error=raise,gcc__cxxflags=-pipe
-          python -m pytest -r A --verbose --runslow --durations=50 --cov=pytensor/ --cov-report=xml:coverage/coverage-${MATRIX_ID}.xml --no-cov-on-fail $PART --benchmark-skip
+          pytest -r A --verbose --runslow --durations=50 --cov=pytensor/ --cov-report=xml:coverage/coverage-${MATRIX_ID}.xml --no-cov-on-fail $PART --benchmark-skip
         env:
           MATRIX_ID: ${{ steps.matrix-id.outputs.id }}
           MKL_THREADING_LAYER: GNU
@@ -231,7 +231,7 @@ jobs:
         shell: micromamba-shell {0}
         run: |
           export PYTENSOR_FLAGS=mode=FAST_COMPILE,warn__ignore_bug_before=all,on_opt_error=raise,on_shape_error=raise,gcc__cxxflags=-pipe
-          python -m pytest --runslow --benchmark-only --benchmark-json output.json
+          pytest --runslow --benchmark-only --benchmark-json output.json
       - name: Store benchmark result
         uses: benchmark-action/github-action-benchmark@v1
         with: