Extension ignores `TransactionRequest.nonce` passed from dapp

[Velenir]

Describe the bug
I want to be able to initate transaction cancellation from inside the dapp. So I pass a transaction with nonce = pendingTx.nonce to provider.sendTransaction. But Metamask extension ignores it and uses its internally tracked nonce.

Steps to reproduce (REQUIRED)

1. Enable custom nonce in Metamask (optional, so you see what it uses)
2. Get a few txs pending, so we have legitimate nonces to cancel
3. In browser console

let [acc] = await window.ethereum.enable()
// send 0 ETH from yourself to yourself, give it nonce of one of the pending txs
window.ethereum.request({method: "eth_sendTransaction", params:[{value: 0, to:acc, from:acc, nonce: '0x'+22..toString(16) }]})

4. In Metamask popup (and when executing tx) it still has its internal nonce

Expected behavior
Metamask uses what nonce dapp passes to it

Browser details (please complete the following information):

• OS: Ubuntu 20.04
• Browser: Chrome 96.0.4664.45
• MetaMask Version: 10.6.1

Additional context (Error Messages, etc.)

According to #2699 PR we should be able to specify nonce as long as it's not higher than latest confirmed nonce, so passing nonce of a pending transaction should work, but doesn't.

[danjm]

We did temporarily support this years ago: #2699

Then a few months later, we removed that support 4a3288f

Allowing dapps to specify nonce would be difficult for us. We'd need to communicate to users that a transaction with a future nonce could stay in pending for a long time, possibly forever. It kinda breaks our ability to keep the user’s nonce queue predictable and non-stuck.

Your request to be able to initiate cancelling from your dapp is interesting though. There are ways we could pursue that without giving control of the nonce to dapps.

So this is more of a new feature request than a bug.

[BelfordZ]

Would a new api method for wallet_cancelTransaction do the trick?