Update and delete registration with account reuse (#6174)

* find the correct url when deactivating an acmev1 account on the acmev2 endpoint

* set regr in ClientNetwork.account after deactivating on the server

* update self.net.account

* move logic into update_registration

* return methods to their original order to please git

* factor out common code

* update test_fowarding to use a method that still gets forwarded

* add acme module test coverage

* pragma no cover on correct line

* use previous regr uri

* strip unnecessary items from regr before saving

* add explanation to main.py

* add extra check to client_test.py

* use empty dict instead of empty string to indicate lack of body that we save to disk

certbot/account.py

@@ -270,9 +270,12 @@ class AccountFileStorage(interfaces.AccountStorage):
                 if hasattr(acme.directory, "new-authz"):
                     regr = RegistrationResourceWithNewAuthzrURI(
                         new_authzr_uri=acme.directory.new_authz,
-                        body=regr.body,
-                        uri=regr.uri,
-                        terms_of_service=regr.terms_of_service)
+                        body={},
+                        uri=regr.uri)
+                else:
+                    regr = messages.RegistrationResource(
+                        body={},
+                        uri=regr.uri)
                 regr_file.write(regr.json_dumps())
             if not regr_only:
                 with util.safe_open(self._key_path(account_dir_path),