Publish state on playlist update

Description

This MR consolidates the routines to update and publish state after certain events. This resolves an outstanding defect when adding or removing media from the playlist and simplifies the existing logic.

How Has This Been Tested?

Tested with Pixel 3 running Android 11 and WearOS Watch Emulator

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the CONTRIBUTING section of the README document.

Resolves

Fixes: #2196 (closed)