playground: fix web component sample layout

Author: jogibear9988

docs/playground.html

@@ -311,9 +311,9 @@ <h1>Playground</h1>
 
     // Editor host div
     const div = document.createElement('div');
-    div.style.cssText = 'position:absolute;inset:0';
+    div.style.cssText = 'width:100%;height:100%';
     shadow.appendChild(div);
-    this.style.cssText = 'display:block;position:absolute;inset:0';
+    this.style.cssText = 'display:block;width:100%;height:100%';
 
     link.onload = () => {
       monaco.editor.create(div, {
@@ -339,7 +339,6 @@ <h1>Playground</h1>
   customElements.define('monaco-editor-wc', MonacoEditorElement);
 }
 
-container.style.cssText = 'position:relative';
 const el = document.createElement('monaco-editor-wc');
 container.appendChild(el);
 `,