[video_player_avplay] Fix subtitle crash issue for DASH stream.

[gin7773]

Main changes:

• Update plusplayer
  1. [DASH] Fix subtitle crash issue.

[gemini-code-assist]

Code Review

This pull request updates the "video_player_avplay" package to version 0.8.2, aiming to fix a subtitle crash issue for DASH streams. However, a high-severity vulnerability has been identified in the picture-based subtitle handling logic. The "channels" and "stride" for PNG encoding are calculated from untrusted external input without proper validation, which can lead to out-of-bounds memory access and potential information disclosure. Additionally, there's an issue with incorrect data types being passed to the PNG conversion function, which could cause further problems.