[core] reject if streamid of group conflict

[gou4shi1]

Fix part of #1838

[maxsharabayko]

The targeted situation is two (or more) independent groups of callers that happen to have the same Group ID.
If those were configured at least with different StreamIDs, the value can be used to avoid accepting a connection from a different group after a connection from the first one is accepted.
Once the first group member connection is accepted, its Stream ID (if set) is saved for the group. Further member connection requests with a different Stream ID are rejected.

Will a connection be rejected if StreamID on of the listening group is not configured before it starts listening?
Could that be rather managed via SRT listener callback?

[gou4shi1]

Will a connection be rejected if StreamID on of the listening group is not configured before it starts listening?

Sorry but I couldn't get this point.

Could that be rather managed via SRT listener callback?

Did you mean srt_connect_callback()? In the listener side, it seems only be called in completeBrokenConnectionDependencies()