Notification preference checkbox stays toggled when saving fails #4233

Initial Checklist

• I understand this is a bug report and questions should be posted in the Community Discussions
• I searched issues and couldn’t find anything (or linked relevant results below)

Bug Description

When saving a notification preference fails, the error toast appears but the checkbox stays in its new state, so the page shows a setting that wasn't saved. accountPreferences.vue only updates the values after a successful save, so the prop never changes and the native checkbox keeps the toggled state. The "Receive notification mails" checkbox has the same pattern.

Reproduction Steps

1. Open Preferences
2. Make POST /api/v0/settings/values-save fail
3. Click a checkbox in the Notifications table

Expected Outcome

The toast "Unable to save preference…" appears and the checkbox goes back to its saved state.

Actual Outcome

The toast appears, but the checkbox stays toggled until reload.