Add forced logout flow when the proxy is no longer available (#3458)

* Add `MatrixClient.isSlidingSyncProxySupported` function

* Update localazy strings

* Modify `ErrorDialog` to have an `onSubmit` call, which will be used for the submit action.

Also make the title text optional and dismissing the dialog by tapping outside/going back configurable.

* Check if a forced migration to SSS is needed because the proxy is no longer available.

In that case, display the non-dismissable dialog and force the user to log out after enabling SSS.

* Enable native/simplified sliding sync by default.

* Refactor the login to make sure we:

1. Always try native/simplified sliding sync login first, if available.
2. Then, if it wasn't available or failed with an sliding sync not supported error, try with the proxy instead (either discovered proxy or forced custom one).

* Move logic to `LoggedInPresenter` and the UI to `LoggedInView`

* Update screenshots

---------

Co-authored-by: ElementBot <benoitm+elementbot@element.io>

features/login/impl/src/main/res/values-zh/translations.xml

@@ -78,10 +78,4 @@
   <string name="screen_server_confirmation_message_register">"这是您的对话将进行的地方，就像您使用电子邮件提供商来保存电子邮件一样。"</string>
   <string name="screen_server_confirmation_title_login">"即将登录 %1$s"</string>
   <string name="screen_server_confirmation_title_register">"即将在 %1$s 上创建一个账户"</string>
-  <string name="screen_waitlist_message">"目前 %1$s 上 %2$s 的负载很大。过几天再回来试试吧。
-
-感谢您的耐心！"</string>
-  <string name="screen_waitlist_message_success">"欢迎使用 %1$s"</string>
-  <string name="screen_waitlist_title">"马上就好。"</string>
-  <string name="screen_waitlist_title_success">"您已加入。"</string>
 </resources>