[Bug]: batch txs dropped or replaced, should queue up

**Describe the bug**

On desktop, if I send several txs, they get pooled up, prompting the user to either accept the action, reject that one tx, or reject them all.

On mobile, if I send several txs, they are instead replaced, or dropped and replaced by the last one, so instead of having several txs to either accept or reject, I end up having only one.

Desired behaviour: have a pool of txs, with a button to accept the action, reject the action, or reject all the txs at once.
Current behaviour: only the last tx is shown, the previous ones are dropped and replaced.

**Expected behavior**

When sending multiple txs in a batch, have a pool of them, with a button to accept the action, reject the action, or reject all the txs at once.

**Steps to reproduce**

Asynchronically send several txs to MM mobile to be signed on. I'm currently using WalletConnect + ethers v6. On desktop MM shows all the txs in a queue. On mobile, they are dropped and replaced.

**Version**

7.12.3

**Build type**

None

**Device**

iPhone 12 Pro Max

**Operating system**

iOS

**Severity**

I think this is more a nuisance than a bug, as it forces me to send the tx synchronically (i. e. wait until one tx is confirmed or dropped from the blockchain, then send the other, and so on).

Start by reproducing the issue on an iPhone using WalletConnect and ethers v6, sending several transactions asynchronously for signing. Trace the mobile transaction-signing flow and compare it with the desktop queue behavior; done means multiple pending transactions remain available to accept, reject individually, or reject together.

Written by the indexing model from the issue text.