nui vim.ui.select callback is called twice,

[DrKGD]

Describe the bug
NUI vim.ui.select callback is called twice, once for "on_close" and once for "on_submit", not sure if that has always been the case but I just happened to discover it.

NUI Integration in dressing.nvim

System information

• OS: Arch Linux
• Neovim version: NVIM v0.10.0-dev-1840+g97bea3163a
• Is this related to a specific vim.ui.select backend? If so, which one? NUI
• Dressing config:

require('dressing').setup {
  select = {
    backend = { "nui", "fzf_lua", "builtin" },
  }
}

Of course, thats the MRE for me, using lazy.nvim, without lazy loading.

To Reproduce
Steps to reproduce the behavior:

1. Run the following
   :lua vim.ui.select({'a','b'}, { prompt = 'test' }, function(input) print(input) end)
2. Either cancel with Esc, or confirm any of its values, should report both the value itself and an extra nil

By commenting out on_close, nui integration works as intended, not sure if that bring any side effects into the mix 😞

[stevearc]

Should be fixed