Fix missing display of non-freethreaded Python 3.13 in python list (#9669)

Closes https://github.com/indygreg/python-build-standalone/issues/407

```
❯ cargo run -q -- python list | head -n 2
cpython-3.13.0+freethreaded-macos-aarch64-none    <download available>
cpython-3.13.0-macos-aarch64-none                 <download available>
❯ uv python list | head -n 2
cpython-3.13.0+freethreaded-macos-aarch64-none    <download available>
cpython-3.12.7-macos-aarch64-none                 <download available>
```

crates/uv-python/src/installation.rs

@@ -327,6 +327,10 @@ impl PythonInstallationKey {
         &self.libc
     }
 
+    pub fn variant(&self) -> &PythonVariant {
+        &self.variant
+    }
+
     /// Return a canonical name for a minor versioned executable.
     pub fn executable_name_minor(&self) -> String {
         format!(

crates/uv/src/commands/python/list.rs

@@ -115,6 +115,7 @@ pub(crate) async fn list(
                     *key.os(),
                     *major,
                     *minor,
+                    key.variant(),
                     key.implementation(),
                     *key.arch(),
                     *key.libc(),
@@ -130,6 +131,7 @@ pub(crate) async fn list(
                     *major,
                     *minor,
                     *patch,
+                    key.variant(),
                     key.implementation(),
                     *key.arch(),
                     key.libc(),