Don't dispose command when closing connection.

It's unexpected that disposing MySqlCommand would be a side-effect of
CommandBehavior.CloseConnection; the commit that originally introduced
this didn't provide a justification for this behaviour.

Author: bgrainger

src/MySqlConnector/MySql.Data.MySqlClient/MySqlDataReader.cs

@@ -543,10 +543,7 @@ internal async ValueTask DisposeAsync(IOBehavior ioBehavior, CancellationToken c
 				connection.FinishQuerying(m_hasWarnings);
 
 				if ((m_behavior & CommandBehavior.CloseConnection) != 0)
-				{
-					(Command as IDisposable)?.Dispose();
 					await connection.CloseAsync(ioBehavior).ConfigureAwait(false);
-				}
 				Command = null;
 			}
 		}