wasm: Text input hotfix

Focus the canvas on window activation to make the screen receive
key events.

Fixes: QTBUG-111848
Change-Id: Iad3474681653b176eebd901aaf59e84538681351
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

src/plugins/platforms/wasm/qwasmwindow.cpp

@@ -477,6 +477,10 @@ void QWasmWindow::requestActivateWindow()
 
     if (window()->isTopLevel())
         raise();
+
+    if (!QWasmIntegration::get()->inputContext())
+        m_canvas.call<void>("focus");
+
     QPlatformWindow::requestActivateWindow();
 }