Use removeChild instead of remove for compatibility

src/Terminal.ts

@@ -2300,7 +2300,7 @@ export class Terminal extends EventEmitter implements ITerminal, IInputHandlingT
       this.bellAudioElement.setAttribute('src', this.options.bellSound);
       this.element.appendChild(this.bellAudioElement);
     } else if (this.bellAudioElement) {
-      this.bellAudioElement.remove();
+      this.element.removeChild(this.bellAudioElement);
     }
   }
 }