Update plugins based on the review comments.

1. Remove kotlin language server from mason

2. Add optinal is true, only enabled if the user has explicitly enabled
the extra plugin.

3. Remove duplicate dependencies cause they are already defined in the
plugin.

4. Add none-ls as optional

lua/lazyvim/plugins/extras/lang/kotlin.lua

@@ -1,13 +1,9 @@
 return {
-  -- Add linting, debug adapter, language server
+  -- Add packages(linting, debug adapter)
   {
     "williamboman/mason.nvim",
     opts = function(_, opts)
-      vim.list_extend(opts.ensure_installed or {}, {
-        "ktlint",
-        "kotlin-language-server",
-        "kotlin-debug-adapter",
-      })
+      vim.list_extend(opts.ensure_installed or {}, { "ktlint", "kotlin-debug-adapter" })
     end,
   },
   -- Add syntax highlighting
@@ -20,7 +16,6 @@ return {
   -- Add language server
   {
     "neovim/nvim-lspconfig",
-    dependencies = "williamboman/mason.nvim",
     opts = {
       servers = {
         kotlin_language_server = {},
@@ -30,24 +25,37 @@ return {
   -- Add linting
   {
     "mfussenegger/nvim-lint",
+    optional = true,
     dependencies = "williamboman/mason.nvim",
     opts = {
       linters_by_ft = { kotlin = { "ktlint" } },
     },
   },
-  -- Add formatting
+  -- Add formatting as optional
   {
     "stevearc/conform.nvim",
-    dependencies = "williamboman/mason.nvim",
+    optional = true,
     opts = {
       formatters_by_ft = { kotlin = { "ktlint" } },
     },
   },
+  -- Add formatting and linting as optional
+  {
+    "nvimtools/none-ls.nvim",
+    optional = true,
+    opts = function(_, opts)
+      local nls = require("null-ls")
+      opts.sources = vim.list_extend(opts.sources or {}, {
+        nls.builtins.formatting.ktlint,
+        nls.builtins.diagnostics.ktlint,
+      })
+    end,
+  },
   -- Add debugger
   {
     "mfussenegger/nvim-dap",
+    optional = true,
     dependencies = "williamboman/mason.nvim",
-
     opts = function()
       local dap = require("dap")
       if not dap.adapters.kotlin then