fix(#125): debug(e2): explicitely say that issuer does not exist

end2end-tests/tests/common/cert.rs

@@ -29,12 +29,12 @@ pub async fn certify(client: &Client, from: AccountKeyring, to: AccountKeyring)
         .storage()
         .fetch(&gdev::storage().identity().identity_index_of(&from), None)
         .await?
-        .unwrap();
+        .expect(format!("{} issuer must exist", from.to_string()).as_str());
     let receiver_index = client
         .storage()
         .fetch(&gdev::storage().identity().identity_index_of(&to), None)
         .await?
-        .unwrap();
+        .expect(format!("{} issuer must exist", from.to_string()).as_str());
 
     let _events = create_block_with_extrinsic(
         client,