datastore transactions: remove on ATProto.create_for, narrow in model…

…s.enable

we were doing heavy work like generating RSA keys and external network requests for creating DIDs inside datastore txes, which led to bad contention. details in #1376

atproto.py

@@ -367,7 +367,6 @@ def is_blocklisted(url, allow_internal=False):
         return util.domain_or_parent_in(util.domain_from_link(url), DOMAIN_BLOCKLIST)
 
     @classmethod
-    @ndb.transactional()
     def create_for(cls, user):
         """Creates an ATProto repo and profile for a non-ATProto user.
 

models.py

@@ -537,6 +537,9 @@ def enable_protocol(self, to_proto):
         """
         added = False
 
+        if to_proto.LABEL in ids.COPIES_PROTOCOLS and not self.get_copy(to_proto):
+            to_proto.create_for(self)
+
         @ndb.transactional()
         def enable():
             user = self.key.get()
@@ -547,9 +550,6 @@ def enable():
                 nonlocal added
                 added = True
 
-            if to_proto.LABEL in ids.COPIES_PROTOCOLS and not user.get_copy(to_proto):
-                to_proto.create_for(user)
-
             return user
 
         new_self = enable()