[Bug]: Creating a new Linked Account does not always create a Starting Balance

### Verified issue does not already exist?

- [x] I have searched and found no existing issue

### What happened?

In the discord, multiple users have been asking for help when their account balances to not match reality. The solution is usually that they do not have a Starting Balance transaction.

The workflow for creating a linked account never prompts the user for a start date or starting balance, and relies on the bank sync provider to handle this properly. The workflow should be updated to prompt the user for this information.

### How can we reproduce the issue?

Bug #3218 seems related and describes one case where SimpleFIN fails to create a starting balance.

However, many users experiencing this issue use GoCardless, so there are other cases when this can happen.

### Where are you hosting Actual?

Pikapods

### What browsers are you seeing the problem on?

Chrome, Microsoft Edge

### Operating System

Windows 10

Start by tracing the linked-account creation workflow and review bug #3218 for the related SimpleFIN case. Compare how GoCardless and other bank-sync providers handle initial balances. Done means the workflow prompts for a start date and starting balance and reliably creates the starting balance transaction.

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