App doesn't care if video is downloaded.

Nobody has claimed this yet.

## The Issue

### Steps to reproduce
1. go to a video
2. pause the video (#963)
3. click the download button
4. wait for the video to download. do other stuff on your phone.
5. go to the `Library` section in the LBRY app
6. click the video you downloaded

### Expected behaviour
The video plays smoothly as it's all downloaded.

### Actual behaviour
The video takes a long time to load, and pauses to buffer very often.

## System Configuration
- Device: Pixel 2 XL
- Android version: 10

## Anything Else

App version: 0.15.14
LBRY SDK: 0.76.0

## Screenshots

## Internal Use

### Acceptance Criteria
1.
2.
3.

### Definition of Done
- [ ] Tested against acceptance criteria
- [ ] Tested against the assumptions of the user story
- [ ] The project builds without errors
- [ ] Unit tests are written and passing
- [ ] Tests on devices/browsers listed in the issue have passed
- [ ] QA performed & issues resolved
- [ ] Refactoring completed
- [ ] Any configuration or build changes documented
- [ ] Documentation updated
- [ ] Peer Code Review performed

Reproduce the issue using the listed steps on Android 10 with the reported app and SDK versions, then trace how a downloaded video is opened from the Library section. Confirm that playback uses the completed download rather than buffering, and verify the behavior against the reported device configuration.

Written by the indexing model from the issue text.