Cancel DBCommand after finish reading events by PersistenceId (#5311)

Author: jarlrasm

src/contrib/persistence/Akka.Persistence.Sql.Common/Journal/QueryExecutor.cs

@@ -543,6 +543,7 @@ public virtual async Task SelectByPersistenceIdAsync(DbConnection connection, Ca
                         var persistent = ReadEvent(reader);
                         callback(persistent);
                     }
+                    command.Cancel();
                 }
             }
         }