raft: Handle non-critical config update errors in when changing status

to voter.

When a node is bootstrapped and joins a cluster as a non-voter, errors can occur while committing
a new Raft record, for instance, if the Raft leader changes during this time. These errors are not
critical and should not cause a node crash, as the action can be retried.

Fixes scylladb/scylladb#20814

(cherry picked from commit 8c48f7ad62)

test/topology_custom/test_error_becoming_voter.py

@@ -17,7 +17,6 @@ from test.pylib.util import wait_for_cql_and_get_hosts
 logger = logging.getLogger(__name__)
 
 
-@pytest.mark.xfail(reason="issue #20814")
 @pytest.mark.asyncio
 async def test_error_while_becoming_voter(request: pytest.FixtureRequest, manager: ManagerClient) -> None:
     """