Add support for --no-build-isolation (#2258)

## Summary

This PR adds support for pip's `--no-build-isolation`. When enabled,
build requirements won't be installed during PEP 517-style builds, but
the source environment _will_ be used when executing the build steps
themselves.

Closes https://github.com/astral-sh/uv/issues/1715.

crates/uv-distribution/src/source/mod.rs

@@ -949,6 +949,8 @@ impl<'a, T: BuildContext> SourceDistCachedBuilder<'a, T> {
         editable_wheel_dir: &Path,
     ) -> Result<(Dist, String, WheelFilename, Metadata21), Error> {
         debug!("Building (editable) {editable}");
+
+        // Build the wheel.
         let disk_filename = self
             .build_context
             .setup_build(