ATProto: deregister XRPC methods we don't support

fixes:
* https://console.cloud.google.com/errors/detail/CIGTqdDu7ZPg4QE;time=P30D?project=bridgy-federated
* https://console.cloud.google.com/errors/detail/CPbL1db3m4KzVw;time=P30D?project=bridgy-federated
* https://console.cloud.google.com/errors/detail/CIGTqdDu7ZPg4QE;time=P30D?project=bridgy-federated

flask_app.py

@@ -49,9 +49,22 @@
     # https://github.com/googleapis/python-ndb/issues/888
     cache_policy=lambda key: False)
 
-lexrpc.flask_server.init_flask(arroba.server.server, app)
-
+# deregister XRPC methods we don't support
+for nsid in (
+    'com.atproto.repo.applyWrites',
+    'com.atproto.repo.createRecord',
+    'com.atproto.repo.deleteRecord',
+    'com.atproto.repo.putRecord',
+    'com.atproto.repo.uploadBlob',
+    'com.atproto.server.createSession',
+    'com.atproto.server.getAccountInviteCodes',
+    'com.atproto.server.getSession',
+    'com.atproto.server.listAppPasswords',
+    'com.atproto.server.refreshSession',
+):
+    del arroba.server.server._methods[nsid]
 
+lexrpc.flask_server.init_flask(arroba.server.server, app)
 
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