UX for "Undo Verification" (CRUD/Management of Verified Sessions)

### Steps to reproduce

1. Click on an unverified session of another user
2. Choose to verify by text
3. Accidentally click "verify" when you just want to close the window
4. ...
5. Burn everything. Create a new account because now you've trusted something that's untrusted, and you can't mark it as untrusted??

### Outcome

#### What did you expect?

I should be able to manage other user's trust. If I trusted something in the past, I should be able to see that and change it to "untrusted"

#### What happened instead?

I accidentally marked one contact's untrusted devices as trusted, and now *nothing* is trustworthy >:0

### Operating system

Debian Linux

### Application version

Element version: 1.11.57 Crypto version: Olm 3.2.15

### How did you install the app?

apt

### Homeserver

nitro.chat

### Will you send logs?

No

Start by reviewing the verification flow described in the reproduction steps and the surrounding session-trust UX in the Element client. Done means a user can inspect and change another user's verified session back to untrusted, and closing the dialog cannot accidentally confirm verification.

Written by the indexing model from the issue text.