Multichain: Fix Subscriptions

[jiexi]

Description

On CAIP connection via externally_connectable:

• subscription and middleware for permitted chains are now instantiated on connection open
  • i.e. if you restart your wallet, you should be able to make eth_subscribe calls for previously permitted dapps without having to call wallet_createSession first
• subscription and middleware and are cleaned up on connection clos
  • i.e. you should not get any eth_subscriptions after refreshing the page and reconnecting
• fix CAIP stream pipeline close handler not firing
  • whoops...
• subscription and middleware are now also key'ed by tabId
  • i.e. subscriptions are isolated to the tabs they are started in

Related issues

Fixes: https://github.com/MetaMask/MetaMask-planning/issues/3451

Manual testing steps

const EXTENSION_ID = 'nonfpcflonapegmnfeafnddgdniflbnk';
const extensionPort = chrome.runtime.connect(EXTENSION_ID)
extensionPort.onMessage.addListener((msg) => {
    // format wallet_notify events nicely so that we can read them more easily later
    if (msg.data.method === 'wallet_notify') {
        console.log('wallet_notify:', {
            scope: msg.data.params.scope,
            method: msg.data.params.notification.method,
            subscription: msg.data.params.notification.params.subscription,
            number: msg.data.params.notification.params.result.number
        })
        return;
    }
    console.log(msg.data)
})

extensionPort.postMessage({
    type: 'caip-x',
    data: {
        "jsonrpc": "2.0",
        method: 'wallet_createSession',
        params: {
            requiredScopes: {
            },
            optionalScopes: {
                'eip155:1': {
                    methods: [
                        'eth_sendTransaction', 
                        'eth_subscribe'
                    ],
                    notifications: ['eth_subscription'],
                    accounts: []
                },
                'eip155:11155111': {
                    methods: [
                        'eth_sendTransaction', 
                        'eth_subscribe'
                    ],
                    notifications: ['eth_subscription'],
                    accounts: ['eip155:11155111:0x5bA08AF1bc30f17272178bDcACA1C74e94955cF4', 'eip155:11155111:0xEe166a3eec4796DeC6A1D314e7485a52bBe68e4d']
                },
                'eip155:59141': {
                    methods: [
                        'eth_sendTransaction',
                    ],
                    notifications: [],
                    accounts: []
                },
            },
        },
    }
})


extensionPort.postMessage({
    type: 'caip-x',
    data: {
        "jsonrpc": "2.0",
        method: 'wallet_invokeMethod',
        params: {
            scope: 'eip155:11155111',
            request: {
                "method": "eth_subscribe",
                 "params": [
                     "newHeads"
                ],
            }
        }
    }
})

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[github-actions]

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[jiexi]

TODO make unsubscribe() and removeMiddleware() private