Use nvim_win_hide instead o nvim_win_close for supporting custom menu on cmdwin

lua/cmp/utils/misc.lua

@@ -15,12 +15,6 @@ misc.concat = function(list1, list2)
   return new_list
 end
 
----Return is cmdwin or not.
----@return boolean
-misc.is_cmdwin = function()
-  return vim.fn.getcmdwintype() ~= ''
-end
-
 ---Get cursor before line
 ---@return string
 misc.get_cursor_before_line = function()