feat: add requirement of account id to be public in RPC

rpc/src/server/api.rs

@@ -149,14 +149,20 @@ impl api_server::Api for RpcApi {
         debug!(target: COMPONENT, request = ?request.get_ref());
 
         // Validating account using conversion:
-        let _account_id: AccountId = request
+        let account_id: AccountId = request
             .get_ref()
             .account_id
             .clone()
             .ok_or(Status::invalid_argument("account_id is missing"))?
             .try_into()
             .map_err(|err| Status::invalid_argument(format!("Invalid account id: {err}")))?;
 
+        if !account_id.is_on_chain() {
+            return Err(Status::invalid_argument(
+                "Invalid account id: account required to be public",
+            ));
+        }
+
         self.store.clone().get_public_account_details(request).await
     }
 }