Unable to edit amount after using payment deeplink

### **Description**

This was observed in testing PR 5191 and was confirmed to exist in production. Video below is from iPhone 13 mini running iOS 16 and MetaMask mobile v5.12.3 build 1033.

If the user engages a payment deeplink but wishes to edit the amount, it is not possible without editing the deeplink itself. It may be sensible to present a warning similar to a when a user changes gas as suggeted by a dapp, if a user edits any of the values provided in the payment deeplink.

However, a user should be able to edit payment details or destination when attempting to engage a payment deeplink.

### **Technical Details**

- Since the user did not step through the Send to and amount pages, when they tap "back" after engaging a payment deeplink they are dumped in wallet view or whatever screen was previously viewed.

### **Acceptance Criteria**

- If I tap a payment deeplink and wish to edit the amount, I should be able to make changes when I tap "back" instead of being dumped in wallet view

Scenario: Edit amount after tapping a payment deeplink
- GIVEN a user has tapped a payment deeplink
- WHEN a user taps "back" on the top left corner of the confirm screen
- THEN the user could be brought to the amount page and provided the opportunity to edit the amount
- WHEN the user taps "Back" from the "Amount" page
- THEN they should be able to edit the "To:" address

### **References**

- https://recordit.co/APMlbXgnbp

Start by reproducing the payment deeplink flow on the mobile app, focusing on the confirm, amount, and recipient screens described in the acceptance criteria. Trace the back-navigation behavior after opening a deeplink; done means Back returns to amount editing, then recipient editing, instead of the wallet view.

Written by the indexing model from the issue text.