`New Recovery Method` modal is a total mess

Closely related to #29170; this issue deals with what happens if you wait until the broken session has something to back up.

Start with two sessions, A and B, both of which have all secrets cached locally. Repro steps also work if A is an Element X client.

1. On session A, go to Settings -> Encryption, and disable key storage. Accept the warning and "Delete key storage".
2. Again on session A, *re-enable* key storage. Do **not** set up recovery at this point.
3. Arrange for session B to receive a room key. One way to do this is to `/discardsession` and send a message from session A.
4. Wait a minute or so (See also: #29170)
5. On session B, observe "New Recovery Method" dialog.

6. Click "Set up Secure messages".
7. New dialog opens *behind* the existing one:

8. Close the top dialog so you can see the new one:

(This is `RestoreKeyBackupDialog`. It is only used in this specific situation.)
9. At this point, we don't *have* a recovery key, so this is a surprise.
10. Click "set up new recovery options"

#### What did you expect?

Unclear, to be honest.

#### What happened instead?

`CreateSecretStorageDialog`

This dialog still offers the user the ability to "enter a security phrase". We removed all other instances of it in #30137, but made the conscious decision to leave this instance (https://github.com/element-hq/element-web/issues/30137#issuecomment-2988573769).