Undo the deletion of some tables

changelog.d/5893.misc

@@ -1 +1 @@
-Drop some unused tables.
+Stop populating some unused tables.

changelog.d/6047.misc

@@ -0,0 +1,2 @@
+Stop populating some unused tables.
+

synapse/config/registration.py

@@ -96,7 +96,7 @@ def read_config(self, config, **kwargs):
         self.registration_shared_secret = config.get("registration_shared_secret")
 
         self.bcrypt_rounds = config.get("bcrypt_rounds", 12)
-        self.trusted_third_party_id_servers = config.get(
+        self.trusted_third_party_id_serverstrusted_third_party_id_servers = config.get(
             "trusted_third_party_id_servers", ["matrix.org", "vector.im"]
         )
         account_threepid_delegates = config.get("account_threepid_delegates") or {}