refactor: use lazy's new opts_extend functionality for treesitter and mason

lua/lazyvim/plugins/extras/util/gitui.lua

@@ -3,6 +3,7 @@ return {
   -- Ensure GitUI tool is installed
   {
     "williamboman/mason.nvim",
+    opts = { ensure_installed = { "gitui" } },
     keys = {
       {
         "<leader>gG",
@@ -30,9 +31,5 @@ return {
         end,
       })
     end,
-    opts = function(_, opts)
-      opts.ensure_installed = opts.ensure_installed or {}
-      vim.list_extend(opts.ensure_installed, { "gitui" })
-    end,
   },
 }