Impossible to open vault after iOS 26 upgrade

### Summary

After iOS 26 upgrade it was impossible to open vault with FaceID the vault, like an infinite FaceID loop

### Please agree to the following

- [x] I have searched [existing issues](https://github.com/cryptomator/ios/issues?q=) for duplicates
- [x] I agree to follow this project's [Code of Conduct](https://github.com/cryptomator/ios/blob/develop/.github/CODE_OF_CONDUCT.md)

### System Setup

- iOS: 26.0
- Cryptomator: 2.7.2 (1384)

### Cloud Type

_No response_

### Steps to Reproduce

- I had previously iOS 18.6
- I upgrade to iOS 26
- I want to open my vault, FaceID asked
- FaceID successfull, but asked again
- Endless FaceID checks, vault never opened

### Expected Behavior

My vault is opened

### Actual Behavior

Endless FaceId checks loop, vault never opened

### Reproducibility

Always

### Relevant Log Output

```shell

```

### Anything else?

## Workaround

- Remove vault from Cryptmator
- Open the existing vault in Cryptomator
- Now it works

Start by reproducing the FaceID unlock loop on iOS 26.0 with Cryptomator 2.7.2, following the listed upgrade and vault-opening steps, then inspect the vault unlock flow. Done means an existing vault opens after one successful FaceID check without needing to remove and re-add it.

Written by the indexing model from the issue text.