Fix SelectedNetworkController state corruption when networkClients are removed

[adonesky1]

Fixes: https://github.com/MetaMask/MetaMask-planning/issues/1964

@metamask/selected-network-controller

CHANGED

• The SelectedNetworkController now listens for networkConfiguration removal events on the NetworkController and if a removed networkClientId matches the set networkClientId for any domains in its state, it updates them to the globally selected networkClientId and repoints the proxies accordingly.

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate

[Gudahtt]

Interesting idea to use patches for this. Might be more performant this way? I worry about the potential for a network configuration to be replaced by a different operation though, e.g. move or replace.

At the moment I think remove is the only possibility, but later with data syncing, I am not so sure.

Comparing each selected network client ID with each existing network might be safer.

[Gudahtt]

We could ensure this only runs for config changes by using a selector as well, e.g.

this.messagingSystem.subscribe(
'NetworkController:stateChange',
(networkConfigurations) => {
...
},
(state) => state.networkConfigurations,
)

[Gudahtt]

LGTM, good catch!

The base branch was changed.