Parity issue: There is no dedicated colormap texture for the mangrove swamp biome

The bug

The mangrove swamp biome is one of a handful of biomes which strays from the usual grass.png and foliage.png colormaps. In Bedrock Edition, it has its own colormap, but in Java Edition, it does not, creating a disparity.

This is a valid parity issue as mangrove swamps were added in 1.19, far beyond the 1.15 cutoff for parity reports.

These colormaps appear to have been added in the Nether Update, making this a valid parity issue.

How to fix

Instead of hardcoding the colours for mangrove swamps, introduce the colormap file from Bedrock Edition and use it instead. Attached is the file directly from Bedrock Edition, alongside a version with all unused pixels removed (MC-276842).