[v7.2]: Ensure we're returning the correct type of object

[lloydwatkin]

By @nguyenngoc2505 in #47 (comment)

@lloydwatkin Thanks for the quick fixing, But I've another error.

https://github.com/OLIOEX/janus-ar/blob/main/lib/janus-ar/active_record/connection_adapters/janus_mysql2_adapter.rb#L130-L132

https://github.com/rails/rails/blob/v7.2.0/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb#L113-L115

I think replica_connection.execute(sql) return mysql result not ActiveRecord::Result so may we need to change execute to exec_query. I've try and it worked