Bring `betterplayer` up-to-date with dependencies

[mkelleherUSSA]

I believe this Flutter package is very useful and I wanted to use it on iOS and Android. Unfortunately, there were some issues with Gradle ^8.0 and the namespaces. I was able to get that fixed and also I was having trouble with some dependencies. The changes in this PR allow me to run the package on the following Flutter setup on iOS and Android:

Flutter 3.16.9 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 41456452f2 (5 days ago) • 2024-01-25 10:06:23 -0800
Engine • revision f40e976bed
Tools • Dart 3.2.6 • DevTools 2.28.5