Unsupported layout off the main thread

[pchalupa]

When RNWalletView is rendered, I've got this warning:

Unsupported layout off the main thread

The root cause is this constant, which apparently runs off the main thread. How about replacing it with the measure method?

react-native-wallet/ios/RNWalletModule.swift

Lines 11 to 20 in a0fb6bd

	Constants {
	let passButton = PKAddPassButton()
	return [
	"buttonLayout": [
	"baseWidth": passButton.frame.width,
	"baseHeight": passButton.frame.height
	]
	]
	}