Stuck on login screen, trying to cancel leaves app in unusable state

### Steps to reproduce

Installed the app and went through the login process.

Network connectivity was decent (4G) and the account is not huge (a few large rooms, but no m.org HQ for instance).

After the OIDC login _per se_ and choosing "allow" at the callback screen, Element X stayed stuck on the cancel/allow/signout screen, with an endless spinner.

None of the button reacted or did anything, so i couldn't cancel log in, couldn't "allow" again, and couldn't sign out.

After a few minutes, i chose to go back using the Android back action, which led to a series of OIDC error messages and left the app in an unusable state, as i could not sign out nor finish signing in ("authorization grant not in a pending state").

I was able to capture some screenshots. They should be in order of how things happened.

I eventually deleted the app's data, and started from scratch. This time, i didn't get stuck on the cancel/allow/signout page and was able to get my account to sync:

This took some time, but wasn't worrying as the app was clearly asking me to wait.
I was then finally logged in.

I don't have logs, but i could try to reproduce by wiping app data and logging in again, if requested.

### Outcome

#### What did you expect?
A smooth login process. Information about what the app was doing, if i need to wait.

#### What happened instead?
An endless spinner, unresponsive action buttons and the login process falling apart by both showing behind the scenes info users shouldn't see and leaving the app in a completely unusable state.

### Your phone model

Pixel 2

### Operating system version

GrapheneOS (Android 11)

### Application version and app store

0.1.5 (40001050) from Play Store (via Aurora Store)

### Homeserver

element.io

### Will you send logs?

No

### Are you willing to provide a PR?

No