fix(lang/haskell): Better way to disable nvim-lspconfig

Starting with v6.2.1 haskell-tools.nvim had issues to calculate the
correct count of attached clients (result was always 0). This broke the
state machine which decides which commands to allow (`Hls start` vs.
`Hls restart` and `Hls stop`).

This is fixed by disabling the HLS server setup in nvim-lspconfig.
Morally, the intention of the code hasn't changed. However, this way of
disabling HLS solves the mentioned issue.

lua/lazyvim/plugins/extras/lang/haskell.lua

@@ -139,11 +139,7 @@ return {
   {
     "neovim/nvim-lspconfig",
     opts = {
-      setup = {
-        hls = function()
-          return true
-        end,
-      },
+      servers = { hls = { enabled = false } },
     },
   },
 }