re-allow interaction during trackball animation

- was disallowed as a stop-gap measure
- ok after improving temporal multi sampling

src/mol-canvas3d/canvas3d.ts

@@ -444,7 +444,7 @@ namespace Canvas3D {
             }
 
             draw();
-            if (!camera.transition.inTransition && !controls.props.spin && !webgl.isContextLost) {
+            if (!camera.transition.inTransition && !webgl.isContextLost) {
                 interactionHelper.tick(currentTime);
             }
         }