Don't show webview overlay by default

If there is an error while resolving the webview itself, this invisible container can end sticking around incorrectly until the input it destoryed. Better to make sure it is hidden so that it doesn't block user input

src/vs/workbench/contrib/webview/browser/dynamicWebviewEditorOverlay.ts

@@ -47,6 +47,7 @@ export class DynamicWebviewEditorOverlay extends Disposable implements WebviewEd
 	public get container() {
 		const container = document.createElement('div');
 		container.id = `webview-${this.id}`;
+		container.style.visibility = 'hidden';
 		this._layoutService.getContainer(Parts.EDITOR_PART).appendChild(container);
 		return container;
 	}