Import PackageName from uv-normalize (#15439)

## Summary

This might be unintentional? `PackageName` is re-exported from
`uv-pep508`, so some crates import it from there.

crates/uv-build-frontend/src/error.rs

@@ -13,8 +13,8 @@ use tracing::error;
 use uv_configuration::BuildOutput;
 use uv_distribution_types::IsBuildBackendError;
 use uv_fs::Simplified;
+use uv_normalize::PackageName;
 use uv_pep440::Version;
-use uv_pep508::PackageName;
 use uv_types::AnyErrorBuild;
 
 /// e.g. `pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory`
@@ -468,8 +468,8 @@ mod test {
     use std::process::ExitStatus;
     use std::str::FromStr;
     use uv_configuration::BuildOutput;
+    use uv_normalize::PackageName;
     use uv_pep440::Version;
-    use uv_pep508::PackageName;
 
     #[test]
     fn missing_header() {

crates/uv-build-frontend/src/lib.rs

@@ -39,8 +39,8 @@ use uv_distribution_types::{
 };
 use uv_fs::LockedFile;
 use uv_fs::{PythonExt, Simplified};
+use uv_normalize::PackageName;
 use uv_pep440::Version;
-use uv_pep508::PackageName;
 use uv_pypi_types::VerbatimParsedUrl;
 use uv_python::{Interpreter, PythonEnvironment};
 use uv_static::EnvVars;