Integration tests on the various receiver monitoring outcomes

[arminsabouri]

We should follow up with integration tests on the various monitoring outcomes: payjoin tx broadcasted, fallback tx broadcasted, doublespend detected, segwit/non-segwit.... seems important to get these right.

Originally posted by @spacebear21 in #1061 (review)

[mehmetefeumit]

I can give this a go unless someone else is already working on it.

[mehmetefeumit]

We talked about it on Discord and looks like @Mshehu5 has already been doing work on this, so I'm going to look at something else.

[Mshehu5]

@mehmetefeumit go for it many more issues are available