fix: return error when trying to unregister unknown appservice id

src/service/appservice/mod.rs

@@ -143,7 +143,8 @@ impl Service {
             .registration_info
             .write()
             .await
-            .remove(service_name);
+            .remove(service_name)
+            .ok_or_else(|| crate::Error::AdminCommand("Appservice not found"))?;
 
         self.db.unregister_appservice(service_name)
     }

src/utils/error.rs

@@ -85,6 +85,8 @@ pub enum Error {
     #[cfg(feature = "conduit_bin")]
     #[error("{0}")]
     PathError(#[from] axum::extract::rejection::PathRejection),
+    #[error("{0}")]
+    AdminCommand(&'static str),
 }
 
 impl Error {