[Bug]: Converted schedule is incorrect for split transactions with multiple payees

### Verified issue does not already exist?

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

### What happened?

Convert to schedule doesn't work properly for multiple payees since the rules do not set payee explicitly. This breaks split transactions with different payees.

### How can we reproduce the issue?

Create a split transaction with multiple different payees with a future date. Convert to schedule. Post transaction from list of schedules. Check the payees which are now all the same with the parent transaction.

### Where are you hosting Actual?

Fly.io

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

Microsoft Edge

### Operating System

Windows 11