[v3.0.0-beta.3] flyTo Animation Drops frames and stutters

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When triggering the flyTo animation, the map drops frames and the console fills with `'requestAnimationFrame' handler took Xms` warnings. This is happening on the basemap but also legacy styles.

I've tried simplifying the animation and removing things like pitch, explicitly enabling WebGL2, etc. Still, the issue persists to the same level.

**mapbox-gl-js version**: 3.0.0-beta.3

**browser**: Chrome, Firefox, Safari

### Steps to Trigger Behavior

1. Load the map
2. Click a button to zoom from level 5 to 16
3. Check the console to see requestAnimationFrame warnings

### Link to Demonstration

https://jsfiddle.net/garydevenay/1dgu5jh2/23/

### Expected Behavior

Smooth zoom transition without dropped frames

### Actual Behavior

Stuttery animation and lots of dropped frames.

Reproduce the animation from the linked JSFiddle by calling flyTo to zoom from level 5 to 16, then inspect the requestAnimationFrame warnings and frame rate in Chrome, Firefox, and Safari. Compare the basemap and legacy-style cases; done means the transition is smooth without dropped frames or prolonged handler warnings.

Written by the indexing model from the issue text.