chore(filter v2): unsubscribe all with unrelated peer

[romanzac]

Background

After the call of unsubscribe all with unrelated peer, no error is returned to tell developer unsubscribe had no effect.

Details

I wish developer (integrator) could receive error sub message under "could not unsubscribe from peer" with reason describing this peer is unrelated or unsubscribed.

Acceptance criteria

Error is returned to clarify the situation. Existing test "TestUnsubscribeAllUnrelatedPeer" will pass.

[chaitanyaprem]

@romanzac fixed the underlying error in referenced PR, you can modify your test before merging and then close this issue.

[romanzac]

Thanks a lot.