Tiles3d (Pointcloud) + GeotiffSource: Performance issue, frame dropped

This is a continuation / clarification of #595. I did more extensive testing to see where the frame drops where occuring. Even tho I'm not 100% sure it seems like that when a 3d tiles with a point cloud and a sphericalPanorama with a GeotiffSource are both loaded at the same time some frame are partially presented quite often, leading to a stuttering effect of the instance. and it doesn't seem related to how intensive / how well the rendering computer is handling thing. testing on different refresh rate and the rendering always ended up matching the requested frame rate the only thing that changed was the frequencies of those missing frames. I suspect this could have something to do with workers, on the chromium performance devtool tab I generally observe that there is more workers than actual threads on my pc and that when the stuttering happens it concord with all the worker trying to do something at the same time

Summary

Frame seems to be dropped quite often when specifically a 3dtile pointcloud and a sphericalPanorama with a GeotiffSource, might be more general than this but didn't test out other cases.

Steps to reproduce

1. Starting from the point cloud example add a spherical panorama and a geotiff image as a source for it. Here i was using the cat image converted with the options mentionned in #595
2. Be sure to update the panorama position
3. get close to the panorama and move around and you should see the stuttering

Informations

• Giro3D version: current main branch
• Browser (Firefox, Chrome, Opera, Safari...) and version: Arc, Chrome and Firefox
• OS (Linux, MacOS, Windows...): MaxOS