WASM fixes for resize and emscripten >= 3.1.54
- VTK will observe the canvas's parent element for resize events and forward those to SDL2.
- Disable HI-DPI in SDL2 as it is managed by VTK inside the resize observer. Otherwise, SDL2 messed up the canvas style.
- Existing wasm apps do not need to make any change and should not notice anything new.
Edited by Jaswant Panchumarti (Kitware)