fix queue undefined with audiovideo fmp4

[xmedia-systems]

Resolves issues: when playing fmp4 source with audiovideo stream no BufferOperationQueue is found causing "queue is undefined" exception

Checklist

• changes have been done against master branch, and PR does not conflict
• new unit / functional tests have been added (whenever applicable)
• API or design changes are documented in API.md

[jwplayer-robot]

Can one of the admins verify this patch?

[robwalch]

Please add steps to reproduce (with a test stream if possible), and add tests to tests/unit/controller/buffer-operation-queue.ts

[robwalch]

This has been addressed in jwplayer:LHLS:

controller/buffer-operation-queue.ts

export default class BufferOperationQueue {
  private buffers: SourceBuffers;
  private queues: BufferOperationQueues = {
    video: [],
    audio: [],
    audiovideo: []
  };

types/buffers.ts

export interface BufferOperationQueues {
  video: Array<BufferOperation>;
  audio: Array<BufferOperation>;
  audiovideo: Array<BufferOperation>;
}

@xmedia-systems the LHLS branch was rebased (force-pushed) last week and updated this week with the work done upstream in video-dev#2389 and video-dev#2370