Fixes overscrolling on recommended tabs (#881)

## Description
If the continue watching row is empty on recommended pages, it would
scroll to the first successfully loaded row even if previous ones are
still pending.

This PR fixes that so the page waits until the right first row is ready.

### Related issues
Fixes #839

### Testing
Emulator & shield 2019

## Screenshots
N/A

## AI or LLM usage
None

app/src/main/java/com/github/damontecres/wholphin/util/LoadingState.kt

@@ -48,6 +48,9 @@ sealed interface RowLoadingState {
 sealed interface HomeRowLoadingState {
     val title: String
 
+    val completed: Boolean
+        get() = this is Success || this is Error
+
     data class Pending(
         override val title: String,
     ) : HomeRowLoadingState