Use fully-qualified edxnotes app name when checking if installed

common/lib/xmodule/xmodule/edxnotes_utils.py

@@ -10,8 +10,8 @@ def edxnotes(cls):
     """
     Conditional decorator that loads edxnotes only when they exist.
     """
-    if "edxnotes" in sys.modules:
-        from edxnotes.decorators import edxnotes as notes
+    if "lms.djangoapps.edxnotes" in sys.modules:
+        from lms.djangoapps.edxnotes.decorators import edxnotes as notes
         return notes(cls)
     else:
         return cls