feat(2d): add video component property getter (#240)

I added get functions (`isPlaying`, `getCurrentTime` and `getDuration`) to provide
access to these properties which is needed in some cases.

Before there was a 'hacky' way of accessing them via the
`indexing operator` (`[]`).

```ts
videoRef()['playing']()
```

With these changes these properties can be used in a cleaner and
secure way without interfering with core logic.

```ts
videoRef().isPlaying()
```

packages/2d/src/components/Video.ts

@@ -51,6 +51,18 @@ export class Video extends Rect {
     super(props);
   }
 
+  public isPlaying(): boolean {
+    return this.playing();
+  }
+
+  public getCurrentTime(): number {
+    return this.time();
+  }
+
+  public getDuration(): number {
+    return this.video().duration;
+  }
+
   protected override desiredSize(): SerializedVector2<Length> {
     const custom = super.desiredSize();
     if (custom.x === null && custom.y === null) {