Make test compliant with new country_id method

src/phone_number.rs

@@ -299,7 +299,10 @@ mod test {
         #[case] country: Option<country::Id>,
         #[case] _type: Type,
     ) -> anyhow::Result<()> {
-        assert_eq!(country, number.country().id());
+        // Flatten the error into an Option.
+        // XXX: We can't currently distinguish an error case from an unavailable case, given the
+        // current phone number list in rstest above.
+        assert_eq!(country, number.country().id().ok().flatten());
 
         Ok(())
     }