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

---------

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

libraries/designsystem/src/main/kotlin/io/element/android/libraries/designsystem/atomic/molecules/DialogLikeBannerMolecule.kt

@@ -39,6 +39,7 @@ fun DialogLikeBannerMolecule(
     onSubmitClick: () -> Unit,
     onDismissClick: (() -> Unit)?,
     modifier: Modifier = Modifier,
+    actionText: String = stringResource(CommonStrings.action_continue),
 ) {
     Box(modifier = modifier.padding(horizontal = 16.dp, vertical = 8.dp)) {
         Surface(
@@ -74,7 +75,7 @@ fun DialogLikeBannerMolecule(
                 )
                 Spacer(modifier = Modifier.height(12.dp))
                 Button(
-                    text = stringResource(CommonStrings.action_continue),
+                    text = actionText,
                     size = ButtonSize.Medium,
                     modifier = Modifier.fillMaxWidth(),
                     onClick = onSubmitClick,