wasm: disable the canvas resize observer

We’re seeing crashes on tab close and also when the
page has been open for a minute or two. Skip installing
the handler until we figure out what’s wrong.

Pick-to: 5.15
Fixes: QTBUG-93713
Change-Id: Idd0c4d646de544ebdd2f4d00425faa08645335ac

Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: David Skoland <david.skoland@qt.io>
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

src/plugins/platforms/wasm/qwasmscreen.cpp

@@ -57,7 +57,6 @@ QWasmScreen::QWasmScreen(const emscripten::val &canvas)
 {
     m_compositor = new QWasmCompositor(this);
     m_eventTranslator = new QWasmEventTranslator(this);
-    installCanvasResizeObserver();
     updateQScreenAndCanvasRenderSize();
     m_canvas.call<void>("focus");
 }