Add banner for optional migration to simplified sliding sync (#3429)

* Add banner for optional migration to native sliding sync

- Add `MatrixClient.isNativeSlidingSyncSupported()` and `MatrixClient.isUsingNativeSlidingSync` to check whether the home server supports native sliding sync and we're already using it.
- Add `NativeSlidingSyncMigrationBanner` composable to the `RoomList` screen when the home server supports native sliding sync but the current session is not using it.
- Add an extra logout successful action to the logout flow, create `EnableNativeSlidingSyncUseCase` so it can be used there.

* Update screenshots

* Make sure the sliding sync migration banner has lower priority than the encryption setup ones

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

features/logout/api/src/main/kotlin/io/element/android/features/logout/api/LogoutEntryPoint.kt

@@ -16,6 +16,7 @@ interface LogoutEntryPoint : FeatureEntryPoint {
     fun nodeBuilder(parentNode: Node, buildContext: BuildContext): NodeBuilder
 
     interface NodeBuilder {
+        fun onSuccessfulLogoutPendingAction(action: () -> Unit): NodeBuilder
         fun callback(callback: Callback): NodeBuilder
         fun build(): Node
     }