[Feature Request]: Disable branding favicon

### Is there an existing issue for this?

- [x] I have searched the existing issues and checked the recent builds/commits

### What would your feature do ?

#3787 broke custom branding/extension .favicons by forcing the brand .favicon. It would be nice to have an option to disable the brand .favicon in case the user already has a custom .favicon.

### Proposed workflow

1. Open settings
2. Open Appearance
3. Disable default .favicon toggle (defaults to off)

### Additional information

_No response_

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