Scroll to current chapter on playback overlay (#964)

## Description
This PR makes it so when you open the playback overlay and move down to
the "Chapters" row, the first focused chapter will be the current one
instead of always the first one.

### Related issues
Closes #695
Closes #951

### Testing
Emulator

## Screenshots
N/A

## AI or LLM usage
None

app/src/main/java/com/github/damontecres/wholphin/data/model/Chapter.kt

@@ -31,6 +31,7 @@ data class Chapter(
                             )
                         },
                     )
-                }.orEmpty()
+                }?.sortedBy { it.position }
+                .orEmpty()
     }
 }