Create separate target for GravatarOpenAPI generated models

[andrewdmontgomery]

…posing types

Closes #

Description

Testing Steps

[wpmobilebot]

📲 You can test the changes from this Pull Request in Gravatar UIKit Prototype Build by scanning the QR code below to install the corresponding build.

	App Name	Gravatar UIKit Prototype Build
	Build Number	1287
	Version	1.0
	Bundle ID	com.automattic.gravatar-sdk-demo-uikit.prototype-build
	Commit	a47aaf6
	App Center Build	Gravatar SDK Demo - UIKit #146

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Gravatar SwiftUI Prototype Build by scanning the QR code below to install the corresponding build.

	App Name	Gravatar SwiftUI Prototype Build
	Build Number	1287
	Version	1.0
	Bundle ID	com.automattic.gravatar-sdk-demo-swiftui.prototype-build
	Commit	a47aaf6
	App Center Build	Gravatar SDK Demo - SwiftUI #145

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.