This is the skiko part of
https://youtrack.jetbrains.com/issue/COMPOSE-1149/wasm-js-Remove-media-events-from-Skiko

This commit introduces following changes:

 * CanvasRenderer is html-agnostic and deals with NativePointer
* SkiaLayer does not set any DOM dimensions of the canvas - it's up to
the user of the Skia to resolve this dimensions
 * Media event listeners are removed completely