[Bug]: Account Sync - `user-storage-api` response returns 15 accounts, but I'm seeing 10, with incorrect naming for the last one, which updated after adding HW accounts

### Describe the bug

After onboarding with an imported SRP, I see how the `https://user-storage.api.cx.metamask.io/api/v1/userstorage/accounts` returns 15 entries, but I am seeing only 10 in my wallet.
Additionally, the last account displays an incorrect number 11 (instead of 10). After that, when I added 2 trezor accounts, I saw that the Account 11 updated its value to 10

### Expected behavior

_No response_

### Screenshots/Recordings
Initial onboarding, without any action performed.

After adding 2 Trezor accounts, the last Account 11, updated to 10


Uploading actt-sync.mp4…

### Steps to reproduce

This is happening to my SRP, so it's likely hard to repro with another one, but happy to debug in a call.
1. Perform onboarding with an SRP
2. Check account list
3. Check network response

### Error messages or log output

_No response_

### Detection stage

On the development branch

### Version

develop

### Build type

None

### Browser

Chrome

### Operating system

Linux

### Hardware wallet

_No response_

### Additional context

_No response_

### Severity

_No response_

Start by reproducing onboarding with an imported SRP, then compare the account list with the user-storage-api response at /api/v1/userstorage/accounts. Verify why 15 returned entries produce only 10 visible accounts and why the final account is numbered 11 before and after adding two Trezor accounts; the issue provides no named files or tests.

Written by the indexing model from the issue text.