openindoor: Port 8432: Conflicts with another plugin and makes JOSM unable to startup due to conflict in port usage.

[osmidal]

Ahoj,

the plugin "openindoor" and another plugin (I do not know which) do conflict:

When I install both, and (re)start JOSM, it fails to start before even showing the UI, because two plugins want to use port 8432:

`
[...]
2024-07-23 18:42:19.946 INFO: loading plugin 'openindoor-1.0.2-josm' (version UNKNOWN)

====================Server Details====================
Server Machine: [censored].localdomain
Port number: 8432

Error occured:Address already in use
`

I suggest to not block starting up but to show a dialogue telling about the port conflict and pointing the user to where to change the port number (within the GUI) to solve the conflict.

Regards!