radicle: schemars test should be behind feature flag — heartwood

A #[cfg(feature = "schemars")] was missed in the profile/config.rs module since it was part of the test module.

 #[cfg(test)]
 #[allow(clippy::unwrap_used)]
 mod test {
     #[cfg(feature = "schemars")]
     #[test]
     fn schema() {
         use super::Config;