Use legacy environment enabled build for draco decoder module

[ggetz]

CC #6399

There's an error when loading the draco decoder module in IE as the build of the deocder we are using (https://github.com/google/draco#javascript-encoderdecoder) does not support IE as it is a "Legacy environment". We need to use a version built with legacy support.

[pjcozzi]

Isn't this duplicate with #6399?

Did we ship 1.44 with Draco not working IE? Does it at least fail gracefully?

[ggetz]

Closed #6399 to allow it it fail gracefully, and opened this as we need to rebuild the draco module itself.

[mramato]

@ggetz is this fixed with #6420? If not, is it still planned for May 1?

[ggetz]

This was not fixed in #6420, I will try to take a look this afternoon or tomorrow to see if we can get this in for May 1.

[mramato]

@ggetz are you actively working this? It's currently holding up several other Cesium PRs.

[ggetz]

@mramato Sorry, I know it's holding up PRs, but I'm not sure I'll be able to get to it this week with other deadlines.

[mramato]

@pjcozzi any thoughts here? Lack of Draco in IE11 is holding up both Draco point cloud support and updating all of the default ion tilesets to Draco. I was really hoping to have Draco assets in Cesium for FOSS4G since they are so much smaller/faster.

One option is to just not worry about IE11 in master but make sure we fix in for June 1.

[pjcozzi]

Sorry we need to finish the 3D Tiles spec tweaks first - will only be a few days.