Improvements to subtitle search & download (#1728)

## Description
Changes to searching & downloading subtitles:
- Activating newly downloaded subtitles more reliably
- Better audio index adjustment checks after downloading subtitles
- Sort subtitle downloadable options by whether the file hash matches
first
- Update the UI for subtitle downloadable options

Also, some improvements to the subtitle choice dialog:
- It now loops from top to bottom (and vice versa)
- It now focuses initially on current choice

### Dev notes
This PR now the selected tracks from `state.currentItemPlayback` to
`state.currentPlayback`. `currentItemPlayback` now only reflects the
user's choices saved in the database instead of a combination of DB and
"actual" state. `currentPlayback` stores the actual, resolved track
indexes regardless of how they were derived.

This means the indexes values in `state.currentItemPlayback` and
`state.currentPlayback` may be different. For example, if the user has
chosen "Only forced", `state.currentItemPlayback==-3` but
`state.currentPlayback` might be an actual forced track index.

### Related issues
Fixes #1549
Fixes #1718
Closes #1723
Fixes bug reported in
https://github.com/damontecres/Wholphin/issues/1498#issuecomment-5019965271

### Testing
Emulator

## Screenshots

Now shows SDH & hash matching

<img width="779" height="280" alt="image"
src="https://github.com/user-attachments/assets/4c33e5af-c9a1-4c9c-8217-6bc2ab3fcd27"
/>

## AI or LLM usage
None

app/src/main/res/values/strings.xml

@@ -872,4 +872,6 @@
     <string name="override_user_profile_settings">More user profile settings</string>
     <string name="override_user_profile_settings_summary">Override your user profile settings from the server</string>
     <string name="any_language">Any language</string>
+    <string name="hash_matches">Hash matches</string>
+    <string name="subtitles_hearing_impaired">SDH</string>
 </resources>