Fix order-dependent test isolation in test_legal_links

The streamlit mock was installed into sys.modules, but src.common.common
was only popped AFTER importing get_legal_links. When test_gui.py runs
first (CI order: `pytest test_gui.py tests/`), it imports the real,
streamlit-bound common module into sys.modules; the subsequent mock-based
import here was then a cache hit returning the real-streamlit-bound
function, so the tests' session_state overrides had no effect and
get_legal_links returned the OpenMS defaults. The two override tests
failed in CI (they passed locally only when collected first).

Pop src.common.common BEFORE the import to force a fresh import under the
mock, then restore the original module afterward so the AppTest-based test
modules still get the genuine package. Full suite: 76 passed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WCamMNCunp9T2aScEKKUvx

Author: claude

tests/test_legal_links.py

@@ -67,6 +67,11 @@ def __setattr__(self, name, value):
 _saved_modules = {name: sys.modules.get(name) for name in _MOCKED_MODULES}
 sys.modules.update(_MOCKED_MODULES)
 
+# Force a FRESH import of src.common.common under the streamlit mock, even if an
+# earlier test module (e.g. test_gui.py) already imported the real-streamlit-bound
+# version. Save whatever was cached first so we can restore it afterwards.
+_saved_common = sys.modules.pop("src.common.common", None)
+
 from src.common.common import get_legal_links, DEFAULT_LEGAL_LINKS  # noqa: E402
 
 # Restore the real modules (or remove ones that weren't present) so that other
@@ -76,10 +81,15 @@ def __setattr__(self, name, value):
         sys.modules.pop(_name, None)
     else:
         sys.modules[_name] = _orig
-# Drop the cached common module that was imported under the mocks so AppTest
-# re-imports it fresh with the real streamlit. get_legal_links keeps working: it
-# holds a reference to the same `mock_streamlit` object we mutate in the tests.
-sys.modules.pop("src.common.common", None)
+# Restore the original cached common module (the real-streamlit-bound one, if
+# any) so AppTest-based test modules keep getting the genuine package.
+# get_legal_links keeps working: it holds a reference to the freshly-imported
+# mock-bound module's globals (and the same `mock_streamlit` object the tests
+# mutate).
+if _saved_common is None:
+    sys.modules.pop("src.common.common", None)
+else:
+    sys.modules["src.common.common"] = _saved_common
 
 
 def setup_function(_):