bug: OptionSet autocommand is clearing the Neovim intro screen

[mikesmithgh]

Steps to reproduce

• mkdir -p ~/.config/deviconsnvim
• create the file ~/.config/deviconsnvim/init.lua

  
  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-tree/nvim-web-devicons", enabled = true, lazy = false, config = function() require("nvim-web-devicons").setup() end, })

- `export NVIM_APPNAME=deviconsnvim`
- open `nvim`
- lazy.nvim will install nvim-web-devicons
- close `nvim`
- open `nvim`

### Expected
You should see the neovim intro screen

### Actual
You see a blank buffer

## Notes
I performed a git bisect to find the commit that introduced this issue.

commit e283ab937e0197b37ec5d8013e49495193407324 added the `OptionSet` autocommand https://github.com/nvim-tree/nvim-web-devicons/blob/master/lua/nvim-web-devicons.lua#L499

When `set_up_highlights(true)` executes, the intro screen is cleared.

## Demo

https://github.com/nvim-tree/nvim-web-devicons/assets/10135646/fef0ca3f-49ac-475c-8d91-805f6902e8a3

[gegoune]

I tried to reproduce and realised that I am not getting intro screen even with nvim --clean on v0.10.0-dev-1881+g6abdc1ac1-Homebrew.

[mikesmithgh]

@gegoune hmm.. I just tested nvim v0.9.4 and cannot reproduce either. Maybe this is an issue on nightly then. I'll pull latest and report to Neovim core if it is still happening.

[mikesmithgh]

@gegoune I reported to Neovim https://github.com/neovim/neovim/issues/26677. Thanks for taking a look, feel free to close this issue if you want.