Protocol.receive: drop fed.brid.gy domain check

this happens after protocols pre-process objects and eg fill in BF AP actor ids. moved this check to *.send and user entity pre post hooks instead. for #597

protocol.py

@@ -375,14 +375,6 @@ class Protocol:
         if not id:
             error('No id provided')
 
-        # block intra-BF ids
-        if util.domain_from_link(id) in common.DOMAINS:
-            error(f'{id} is on a Bridgy Fed domain, which is not supported')
-        for field in 'id', 'actor', 'author', 'attributedTo':
-            val = as1.get_object(obj.as1, field).get('id')
-            if util.domain_from_link(val) in common.DOMAINS:
-                error(f'{field} {val} is on Bridgy Fed, which is not supported')
-
         # short circuit if we've already seen this activity id.
         # (don't do this for bare objects since we need to check further down
         # whether they've been updated since we saw them last.)

tests/test_protocol.py

@@ -1,4 +1,5 @@
 """Unit tests for protocol.py."""
+from unittest import skip
 from unittest.mock import patch
 
 from flask import g
@@ -1074,6 +1075,7 @@ class ProtocolReceiveTest(TestCase):
         self.assertEqual('fake:stop-following', obj.key.id())
         self.assertEqual('fake:user:target', target)
 
+    @skip
     def test_receive_from_bridgy_fed_domain_fails(self):
         with self.assertRaises(BadRequest):
             Fake.receive({