Invalidate cache when --config-settings change (#7139)

## Summary

If `--config-settings` are provided, we cache the built wheels under one
more subdirectory.

We _don't_ invalidate the actual source (i.e., trigger a re-download) or
metadata, though -- those can be reused even when `--config-settings`
change.

Closes https://github.com/astral-sh/uv/issues/7028.

crates/uv-dispatch/src/lib.rs

@@ -223,6 +223,7 @@ impl<'a> BuildContext for BuildDispatch<'a> {
             &BuildOptions::default(),
             self.hasher,
             self.index_locations,
+            self.config_settings,
             self.cache(),
             venv,
             &markers,