test: relax video-enrichment isolation check (comment mentions music side)

The whole-file 'music' substring check tripped on a comment ('only polls on the
video side, so the engine isn't spun up on the music side'). Replaced with the
meaningful checks: no music API path (/api/enrichment/) and no music modal call
(openEnrichmentManager).

tests/test_video_side_shell.py

@@ -251,7 +251,9 @@ def test_video_enrichment_module_referenced_and_isolated():
     assert "(function" in src and "})();" in src
     assert "window." not in src
     assert "/api/video/enrichment/" in src
-    assert "music" not in src.lower()
+    # No music API/function calls (a comment may mention the music *side*).
+    assert "/api/enrichment/" not in src
+    assert "openEnrichmentManager" not in src
 
 
 def test_video_settings_module_referenced_and_isolated():