dApp/SDK: Prevent Light Client from entering a closing state when user closes a channel but rejects MetaMask prompt

[taleldayekh]

User Story

As Chris I want my wallet confirmation, e.g. MetaMask to be the final say in whether a channel closing should happen or not.

While doing user testing it became obvious that in a real world use-case a user familiar with rejecting transactions in their wallet expects to be able to do so when using the LC as well despite the confirmation dialogs in the dApp.

We should make adjustments to better meet the users expectations in this case and not put the channels in a unusable state when a channel close is not actually happening.

Since MetaMask in this case is the last confirmation step it makes sense that it should be the final say on whether a channel enters a closing state or not.

Acceptance criteria

Tasks