## Problem
We currently have 2 libraries for schema validation: `yup` that was used
with `formik` and `zod` which is now the preferred one.
## Solution
Migrate the MFA settings form to use `zod`.
No visual changes.
<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit
* **Refactor**
* MFA settings forms now use stronger, consistent schema validation with
numeric input coercion and improved typing for more reliable form
behavior.
* Simplified form reset/synchronization for more predictable state
updates.
* **Bug Fixes**
* MFA update requests now send only intended fields.
* Fixed Enhanced MFA Security “Save changes” button to show the correct
loading state.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Gildas Garcia
e95f1cc67c