Strange behavior when trying to log in with a WP.com account while email login is not allowed

[itsmeichigo]

Description When logging in with a WP.com account while email login is not allowed, we are displaying a screen asking for WPCom credentials, but the copy is asking for store credentials. After navigating back from that screen, and tap the Continue button again, the loading indicator shows on the Continue with Apple instead.

Steps to reproduce

• Get into the "Get Started" flow to log in with a WPCom account.
• Enter the email of your account and tap Continue.
• If your account is not allowed to log in with email, a new screen is displayed asking for WPCom username. The copy on this screen asking for store credential for WP.com.
• Tap back, and retry the login. Notice that the loading indicator shows on the Continue with Apple button.

Screencast

https://user-images.githubusercontent.com/5533851/210955439-413b963b-de5a-4619-b265-d7df41a1e8eb.mp4

[itsmeichigo]

Possible solution: use the same field for both email and username for WPCom login. This is the solution we are using in Woo for the WPCom login flow for Jetpack setup: https://github.com/woocommerce/woocommerce-ios/pull/9040.