Improve MUC error handling (don't try to respond to responses)

Description

When an entity sends an IQ stanza to a MUC, the implementation checks if the entity is in the room. If that's not the case, an error is returned. Such an error should not be generated if the original stanza is an IQ result or error.

Environment

None
Fixed

Assignee

Guus der Kinderen

Reporter

Guus der Kinderen