[Bug]: Shield - `Failed to start subscription with card Error: tab action failed`

Nobody has claimed this yet.

### Describe the bug

Whenever I am in the process of subscribing to the Shield plan and I close the subscription page, I get the error `Failed to start subscription with card Error: tab action failed`

### Expected behavior

The error should be handled, so there are no console errors

### Screenshots/Recordings

https://github.com/user-attachments/assets/fb14041c-4c90-4272-b6cc-8c1aec504f1f

### Steps to reproduce

1. Go to Settings > Transaction Shield
2. Activate a plan --> see new tab is open and MM loading
3. Close the tab --> see console error

### Error messages or log output

```shell

```

### Where was this bug found?

Live version (from official store)

### Version

13.40.0

### Build type

None

### Browser

Chrome

### Operating system

MacOS

### Hardware wallet

_No response_

### Additional context

_No response_

### Severity

_No response_

Start at Settings > Transaction Shield and reproduce the flow in Chrome by closing the subscription tab while it is loading. Trace the tab-close handling associated with “Failed to start subscription with card” and adjust the error handling so an intentional close produces no console error. Verify the reproduction steps and expected behavior afterward.

Written by the indexing model from the issue text.