Install clang with the Rust dev environment instead of for everyone (#14967)

Nothing in the base install builds with clang: Qt apps and Ruby's native
gems compile with gcc, and Ruby comes prebuilt from mise. Rust crates that
use bindgen, including rb-sys gems, need libclang, so the Rust dev
environment installs it. llvm was unused even there.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

install/omarchy-base.packages

@@ -15,7 +15,6 @@ bolt
 brightnessctl
 btop
 chromium
-clang
 cliamp
 cups
 cups-filters
@@ -77,7 +76,6 @@ libsecret
 libvips
 libyaml
 libreoffice-fresh
-llvm
 localsend
 lua51
 luarocks