Account Creation: SIWA requires to tap twice on Continue

### Steps to reproduce

When creating an account with Sign In With Apple, I need to tap twice on the Continue button.

After the first time, there is a text appearing shortly that says it is checking if the user id is available. The next tap does the right thing. The UX looks weird.

Note: I have probably several matrix account created with SIWA

I will share a video in a more private way

### Outcome

#### What did you expect?
Tapping once on the Continue button should be enough

### Your phone model

iPhoneX

### Operating system version

15.0

### Application version

FTUE TF

### Homeserver

matrix.org

### Will you send logs?

No