Mark `hls-fourmolu-plugin`, `hls-ormolu-plugin` buildable with GHC 9.8

[moonshxne]

I noticed that many plugins are marked as buildable: false for GHC 9.8 because of a dependency on ghc-exactprint. However, having tried to build HLS with nix for GHC 9.8.1, I'm fairly certain that hls-fourmolu-plugin and hls-ormolu-plugin actually don't depend on exactprint (and the latest fourmolu and ormolu already support GHC 9.8).

[michaelpj]

Great, should be easy to verify, CI will tell us.