Fail with exception if management.server.address is set but actuator is on the same port

[philwebb]

As discovered in #22142, it's possible to have a management.server.address that doesn't get applied if the ManagementPortType is SAME. It would be better if we failed hard instead of ignoring the property.

[pcornelissen]

Just to reiterate, it may be also a good idea to add a note in the documentation of management.server.port that it requires server.port to be set when the real port is on a different port and management.server.port is supposed to be 8080.
This is a very hard to track down bug when your settings are ignored in the way it is now.
Or maybe you should force server.port to be set when the management.server.port is set, just to be safe. This would make things easier to document and shouldn't be a big burden.