[PM-25999] Saving Signal Backups key to password manager does not work

### Steps To Reproduce

1. Test them new Signal Backups
2. When creating the backup and the key is generated, click "Save to password manager"

### Expected Result

Bitwarden allows saving the key to the vault.

### Actual Result

Nothing happens

### Screenshots or Videos

_No response_

### Additional Context

On googled devices, so most of them, this instead redirects to the Google Password Manager which is risky

### Build Version

2025.8.1

### What server are you connecting to?

US

### Self-host Server Version

_No response_

### Environment Details

- Device: moto g52
- OS: iodéOS (which is LineageOS 22.2, which is Android 15 QPR2 for all intents and purposes)

### Issue Tracking Info

- [x] I understand that work is tracked outside of Github. A PR will be linked to this issue should one be opened to address it, but Bitwarden doesn't use fields like "assigned", "milestone", or "project" to track progress.