[llvm] Install llvm-23 in libc docker image (PR #210929)

[via llvm-commits]

jinge90 wrote:

> > it has no impact to image size
> 
> This I'm a bit skeptical of, but if I guess `llvm-23` is a metapackage where we already install all of its dependents, it makes sense.
> 
> > we already did the same thing for llvm-23-tools and aligning with llvm-23-tools makes the logic more clear and unified.
> 
> This argument does not make any sense to me. Neither `llvm-23-tools` nor `llvm-23` really seem to indicate that they have `llvm-link` in them. I think keeping `llvm-23` makes the meaning less clear. If `llvm-23` pulls in additional dependencies that we don't already have installed, this will also result in an image size regression.

Hi, @boomanaiden154 
Got it, I will update the PR to directly create a symbolic link for llvm-link once I finished verification locally.
Thanks very much.

https://github.com/llvm/llvm-project/pull/210929