Remove traces of long-deprecated 'Shared' roles support

This was removed in AccessControl since 3.0.7
see zopefoundation/AccessControl@9fb90b7e

CHANGES.rst

@@ -8,6 +8,8 @@ Change Log
 
 - Drop support for Python 3.7.
 
+- Remove traces of long-deprecated 'Shared' roles support.
+
 
 3.0 (2024-01-22)
 ----------------

src/Products/PluggableAuthService/PropertiedUser.py

@@ -155,14 +155,6 @@ def allowed(self, object, object_roles=None):
                 self.getUserName() != 'Anonymous User':
             return 1
 
-        # Check for ancient role data up front, convert if found.
-        # This should almost never happen, and should probably be
-        # deprecated at some point.
-        if 'Shared' in object_roles:
-            object_roles = self._shared_roles(object)
-            if object_roles is None or 'Anonymous' in object_roles:
-                return 1
-
         # Check for a role match with the normal roles given to
         # the user, then with local roles only if necessary. We
         # want to avoid as much overhead as possible.