Possible `scheduleRerender()` needed to redraw non-transcript track?

Testing this track, it seems to work pretty well! I have run into a couple issues, which I'm documenting here in case they point to some issue.

In one test setup of my single-page web application, its viewconf has four tracks. The second track is a `horizontal-multivec` track and the fourth track is a `horizontal-transcripts` track, via the `higlass-transcripts` plugin.

Within the web application, I have the transcripts track object subscribe to the `trackDimensionsModified` event to get the new transcript track height whenever switching between "collapsed" and "all-transcripts-visible" modes:

```
setTimeout(() => {
const self = this;
const transcriptsTrackObj = this.mainHgView.api.getComponent().getTrackObject(
res.data.views[0].uid,
res.data.views[0].tracks.top[3].uid,
);
transcriptsTrackObj.pubSub.subscribe("trackDimensionsModified", (msg) => {
self.setState({
transcriptsTrackHeight: parseInt(transcriptsTrackObj.trackHeight), // <-- get transcript track height
}, () => {
self.updateViewportDimensions(); // <-- recalculate multivec track height
});
});
}, 500);
```

The `updateViewportDimensions()` generates a viewconf with correct dimensions for all tracks. But the multivec track has the wrong (old) height. It does not redraw itself with the correct (new) height, until I manually pan or zoom the parent HiGlass view.

As a workaround, in order to get the multivec track to redraw, I called `scheduleRerender()` on that track.

In this modified call, the `chromatinStateTrackObj` variable refers to the multivec track whose height needs to be adjusted:

```
setTimeout(() => {
const self = this;
const chromatinStateTrackObj = this.mainHgView.api.getComponent().getTrackObject(
res.data.views[0].uid,
res.data.views[0].tracks.top[1].uid,
);
const transcriptsTrackObj = this.mainHgView.api.getComponent().getTrackObject(
res.data.views[0].uid,
res.data.views[0].tracks.top[3].uid,
);
transcriptsTrackObj.pubSub.subscribe("trackDimensionsModified", (msg) => {
self.setState({
transcriptsTrackHeight: parseInt(transcriptsTrackObj.trackHeight), // <-- get transcript track height
}, () => {
self.updateViewportDimensions(); // <-- recalculate multivec track height
chromatinStateTrackObj.scheduleRerender(); // <-- redraw the multivec track
});
});
}, 500);
```

Using `scheduleRerender()` seems to "refresh" the multivec track, so that it renders with the height value specified in the parent viewconf.

I'm not sure if this is a bug, or if I am not using the plugin correctly. I can provide a link to the development site separately (via Slack etc.) if it is helpful to see the issue firsthand.