Fix removes a logger when pass undefined transport

[arpit728]

While working with winston, I found a small bug. When you pass undefined transport in logger.remove() method it removes the logger. Ideally it should not do anything.

You can follow below steps to reproduce this:

const logger = winston.createLogger({
    level: 'info',
    format: winston.format.simple(),
    timestamp: true,
    defaultMeta: { service: 'user-service', deploymentId: 'abcd', 'containerId': 'kube-5' },
});
const consoleLogger = new winston.transports.Console({
    format: winston.format.simple(),
    timestamp: true,
    level: 'debug',
    logId:'console'
});

logger.add(consoleLogger);

logger.info('Hello!'); // This statement logs perfectly

logger.remove(undefined);

logger.info('Hi'); //This statement logs nothing as the logger got removed.