MariaDB Monitor can kill connections from other monitors during switchover

When killing super-user connections to master server during switchover to protect against writes, the monitor only checks for its own connection id and that COMMAND != 'Binlog Dump'. This means that connections from other monitors are detected and killed in case of cooperative monitoring. In 23.08, the connection kill code checks that no more super-user connections to the master server are created after the kill. As monitors will reconnect on connection loss, this can cause switchover to fail as the primary monitor gives up trying to get rid of all the super-users on the master server.

This should be fixed by filtering by connection username. Usually cooperative monitors use the same username to monitor the servers.