CI: remove compatibility tests without plugin

Author: mj-will

.github/workflows/compatibility-tests.yml

@@ -31,13 +31,7 @@ jobs:
         # Install CPU-only version of PyTorch
         pip install torch --index-url https://download.pytorch.org/whl/cpu
         pip install -e .[test]
-        pip install bilby
-    - name: Run bilby compatibility tests (without plugin)
-      run: |
-        python -m pytest --bilby-compatibility -m "bilby_compatibility"
-    - name: Install bilby plugin
-      run: |
-        pip install nessai-bilby
-    - name: Run bilby compatibility tests (with plugin)
+        pip install bilby nessai-bilby
+    - name: Run bilby compatibility tests
       run: |
         python -m pytest --bilby-compatibility -m "bilby_compatibility"