Update NLCD datasets to use custom colormap_name

[anayeaye]

What

Houston-landcover and campfire-nlcd should use colormap_name=nlcd in mdx configuration supply full colormap in renders and mdx which is blocked by the firewall. Update datasets using these collections and any other datasets with related too-long-colormap definition problems.

nlcd-annual-conus working example

https://github.com/NASA-IMPACT/veda-config/blob/develop/datasets/nlcd.data.mdx?plain=1#L31

AC

• houston-landcover layer configuration(s) updated to use custom colormap
• campfire-nlcd layer configuration(s) updated to use custom colormap

[anayeaye]

Note these datasets and underlying collections may be deprecated in the future.