How do I configure live_grep_args mappings when using lazy.nvim as the plugin manager?

[mirandaio]

Below is a minimal init.lua where I try to configure live_grep_args mappings to open a selection when pressing <C-s> but it is not working. Is there anything I am doing wrong when using lazy.nvim? Thanks

local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
  vim.fn.system({
    "git",
    "clone",
    "--filter=blob:none",
    "https://github.com/folke/lazy.nvim.git",
    "--branch=stable", -- latest stable release
    lazypath,
  })
end
vim.opt.rtp:prepend(lazypath)

require("lazy").setup({
  {
    'nvim-telescope/telescope.nvim',
    tag = '0.1.3',
    dependencies = {'nvim-lua/plenary.nvim', 'nvim-telescope/telescope-live-grep-args.nvim'},
    config = function()
      local telescope = require('telescope')
      telescope.load_extension('live_grep_args')
      telescope.setup({
        pickers = {
          find_files = {
            mappings = {
              n = {
                ["<C-s>"] = require('telescope.actions').select_horizontal
              },
              i = {
                ["<C-s>"] = require('telescope.actions').select_horizontal
              }
            }
          }
        },
        extensions = {
          live_grep_args = {
            mappings = {
              n = {
                ["<C-s>"] = require('telescope.actions').select_horizontal
              },
              i = {
                ["<C-s>"] = require('telescope.actions').select_horizontal
              }
            }
          }
        }
      })
    end
  }
})

vim.g.mapleader = ' '

local builtin = require('telescope.builtin')
vim.keymap.set('n', '<leader>ff', builtin.find_files, {})
vim.keymap.set('n', '<leader>fg', ":lua require('telescope').extensions.live_grep_args.live_grep_args()<CR>")