fix(lspconfig): make opts a function (#3311)

`LazyVim.config` gets evaluated during the parsing phase with `opts`
as a table (thus not taking into account changes made in the user's
personal configuration for the icons), so make `opts` a function to
defer the evaluation until the plugin loads.

lua/lazyvim/plugins/lsp/init.lua

@@ -10,7 +10,8 @@ return {
       "williamboman/mason-lspconfig.nvim",
     },
     ---@class PluginLspOpts
-    opts = {
+    opts = function()
+      return {
         -- options for vim.diagnostic.config()
         ---@type vim.diagnostic.Opts
         diagnostics = {
@@ -106,7 +107,8 @@ return {
           -- Specify * to use this function as a fallback for any server
           -- ["*"] = function(server, opts) end,
         },
-    },
+      }
+    end,
     ---@param opts PluginLspOpts
     config = function(_, opts)
       if LazyVim.has("neoconf.nvim") then