Memory leak if `showCloseButton` is false

[AndriyGo]

I have no idea why this occurs and hence want to share it here in case someone understands why it happens.

Basically, whenever the alert is initialised with showCloseButton = false in its appearance there is a memory leak. To test it, you can replace line 65 in ViewController.swift with showCloseButton: false. Then, profile with instruments and check for leaks after clicking on "Show edit".

Any ideas on why this occurs/how to fix this are greatly appreciated.

@vikmeup would be cool if you could look into this.