Rename "Chrome Mobile iOS" -> "Chrome Mobile"

[znarf]

Seems "iOS" is duplicate with the os property and not necessary

[Krinkle]

I think iOS is significant to keep here. At least for the use cases I've had and seen around me, browser_family is generally used/evaluated/indexed on its own, not solely as tuple with os_family+device.

As such, the presence of "iOS" here, is effectively the only thing I can use to realize that this is WebKit/Safari and not Blink/Chrome. I think that's important to retain in statistics, at least until we formalise a proper "renderer" field (per https://github.com/ua-parser/uap-core/issues/215).