FIX: compress brotli assets from web upgrader
FIX: compress brotli assets from web upgrader

Due to a logic bug we forgot to carry over compress brotli.

This was not an issue for years cause if a brotli asset was absent we
would simply serve the non brotli version.

Due to recent changes this is not longer the case

A follow up on core will remove the COMPRESS_BROTLI flag altogether

discourse/docker_manager,discourse/docker_manager,discourse/docker_manager,discourse/docker_manager