Describe the bug

After manually selecting a timezone or pressing the "Sync with system" button, the Timezone field cannot be cleared.

Additionally, I might suggest changing the iconography of the sync button or otherwise labelling it, as it honestly looks like a button to reset the field and may lead to someone leaking info they don't want to.

Reproduction

1. Go to "Settings"
2. Navigate to "Account"
3. Scroll down to "Timezone"
4. Set a timezone
5. There is no option to clear the field.

Expected behavior

There is an option to clear the field.

Platform and versions

1. OS: Arch Linux
2. Browser: qutebrowser v3.6.3
3. Sable Version: v1.3.1 (5a5b38f)
4. Matrix Homeserver: matrix.org

Additional context

No response