Add unit tests for SwiftUI views

[pinarol]

Let's check how we can add unit tests for SwiftUI Views.

• AvatarPickerView
• QuickEditor
• AvatarGrid
• Probably some other small Views

We can try snapshotting with the existing snapshot library, like:

func testMyViewSnapshot() {
        // Create the SwiftUI view
        let view = MyView()

        let hostingController = UIHostingController(rootView: view)
        hostingController.view.frame = CGRect(x: 0, y: 0, width: 200, height: 100)

        assertSnapshot(matching: hostingController, as: .image)
    }