kUTType was deprecated in iOS15, use UTType instead

[iamgabrielma]

Context

From #1767 :

When the user picks an image from the device media library or took a picture from the device camera, we have to first save it in the app file system and then upload the image given the file URL. The image from the device media library or camera is of type PHAsset, and before we save it for future upload, we'd first export the raw PHAsset to an image with some optimization options.

Description

By updating the minimum release version to iOS 15 recently, we've seen some deprecation warnings. This PR fixes the case for uses of kUTTypeJPEG, kUTTypePNG, and kUTTypeGIF.

This PR does not deal with cases for UTTypeEqual, as it would seems the deprecation message is meant for Objective-C code?

'UTTypeEqual' was deprecated in iOS 15.0: Use -[UTType isEqual:] instead.

Changes

When returning or comparing different file extensions or file types, we change from using kUUType*, to UTType.* instead.

Testing instructions

I'm not 100% sure if I'm handling all test scenarios here, happy to get further feedback about it, but it should be good with the following:

• Confirm that there's no issues uploading JPEG or GIF media types to a product
• Tests should pass

[wpmobilebot]

You can test the changes from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr8093-71b42df on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[jaclync]

Thanks for fixing the warnings in Yosemite tests! I think we can directly compare and use the identifier of any UTType as a string, left some non-blocking suggestions

[jaclync]

nit: I think comparing the identifier strings directly should be fine?

Suggested change

	let gifTypeIdentifier = UTType.gif.identifier as CFString
	if UTTypeEqual(resource.uniformTypeIdentifier as CFString, gifTypeIdentifier) {
	if resource.uniformTypeIdentifier == UTType.gif.identifier {

[jaclync]

nit: similar to above, I think direct string comparison is fine?

Suggested change

	let gifTypeIdentifier = UTType.gif.identifier as CFString
	guard UTTypeEqual(resource.uniformTypeIdentifier as CFString, gifTypeIdentifier) else {
	guard resource.uniformTypeIdentifier == UTType.gif.identifier else {

[iamgabrielma]

Thanks for the review! Removed redundant typecasts here 6530b16 , and UTTypeEqual usage here 71b42df 🎉