[clang] [clang][Diagnostics] Use `enum_select` for `err_builtin_invalid_arg_type` (PR #215480)

[Erich Keane via cfe-commits]

erichkeane wrote:

> It is good to improve such a diagnostic, however I do have two concerns:
> 
>     * The issue #123121 is an omni bus for all diagnostics that are present, so putting fixes {that_issue_number} to PR desc is not correct since this PR only fixes a single diagnostic. The issue can be closed once we can claim that all the issues have been fixed.
> 
>     * The issue is marked as good-first-issue and using AI tools to fix these is not allowed per our AI [policy](https://llvm.org/docs/AIToolPolicy.html)

Both of these are true.  I'm closing this because of the 2nd one, use of AI on a 'good first issue' is strictly prohibited.  The point of these isn't really that the 'need to be done', they are to help new folks learn to contribute to the project, not to get their AI to do work for them.  

https://github.com/llvm/llvm-project/pull/215480