fix(mobile): video player restarting when device rotates

[Sese-Schneider]

Description

Fixes the video player restarting when rotating the device.

Cause was a builder which would create a new GlobalKey every time the device was rotated (and therefore the WidgetTree rebuilt). This new GlobalKey would cause a complete reinitialization of the Widget, rendering the useState useless.

Changed the key to a ValueKey which should still work for the hero animation it was introduced for.
#17362 (comment)

Fixes #16294

How Has This Been Tested?

• Test A
  • open a video in portrait mode
  • rotate the device to landscape
  • video should continue playing and not restart
• Test B
  • open the video
  • video should not be re-initialized

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in the PR.
• I have confirmed that any new dependencies are strictly necessary.
• I have written tests for new code (if applicable)
• I have followed naming conventions/patterns in the surrounding code
• All code in src/services/ uses repositories implementations for database calls, filesystem operations, etc.
• All code in src/repositories/ is pretty basic/simple and does not have any immich specific logic (that belongs in src/services/)

[mertalev]

The global key was essential here when I added this code because of how the hero animation internally renders the target page. I don't think it should be changed to a value key unless we can confirm the video is never reinitialized.

[Sese-Schneider]

@mertalev can you tell me how I can test out the hero animation? I was unable to reproduce this.
Based on my current understanding of the code the ValueKey would have the exact same effect, as the builder is not called again.

Issue with rotation is that the whole tree is rebuilt, and we need a consistent key across rebuilds to avoid the video controller reinitializing

[mertalev]

You can add debug logs to the video player loading methods, including the aspect ratio, video source, etc. They should be called exactly once for an asset.

[Sese-Schneider]

@mertalev thanks for your help, I know understand why the GlobalKey was needed.

I have now introduced the GlobalKey to be created earlier, ensuring it is not thrown away on every rebuild, while staying global during hero animations.
It has been put into the state following Flutter best practices.

Everything has been verified using loggin here on initial load (hero) and by rotating the device.

[shenlong-tanwen]

Thank you!