Onboarding Intro experiment setup

[alessandroboron]

Task/Issue URL: https://app.asana.com/0/0/1207723831937951/f CC: @SabrinaTardio

Description:

This PR is to setup the experiment variants and to show a different onboarding intro based on the variant.

Steps to test this PR:

Scenario 1 - Old Onboarding

1. Setup the variant by using Edit Scheme -> Arguments -> Environment Variables as per attached image.
2. Launch the App Expected Result: The old onboarding should be presented to the user.

Scenario 2 - New Onboarding

1. Setup the variant by using Edit Scheme -> Arguments -> Environment Variables as per attached image.
2. Launch the App Expected Result: The new onboarding should be presented to the user.

<!— Before submitting a PR, please ensure you have tested the combinations you expect the reviewer to test, then delete configurations you know do not need explicit testing.

Using a simulator where a physical device is unavailable is acceptable. —>

Definition of Done (Internal Only):

• [ ] Does this PR satisfy our Definition of Done?

Copy Testing:

• [ ] Use of correct apostrophes in new copy, ie ’ rather than ’

Orientation Testing:

• [ ] Portrait
• [ ] Landscape

Device Testing:

• [ ] iPhone SE (1st Gen)
• [ ] iPhone 8
• [ ] iPhone X
• [ ] iPhone 14 Pro
• [ ] iPad

OS Testing:

• [ ] iOS 15
• [ ] iOS 16
• [ ] iOS 17

Theme Testing:

• [ ] Light theme
• [ ] Dark theme

—

Internal references:

Software Engineering Expectations Technical Design Template

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[alessandroboron]

Wasn't too keen on Onboarding taking on the UIViewController protocol, but I see why you did it.

An alternative would be:

    var controller: (Onboarding & UIViewController)?

    if DefaultVariantManager().isSupported(feature: .newOnboardingIntro) {
        controller = OnboardingIntroViewController()
    } else {
        let storyboard = UIStoryboard(name: "DaxOnboarding", bundle: nil)
        controller = storyboard.instantiateInitialViewController(creator: { coder in
            DaxOnboardingViewController(coder: coder)
        })
    }

    controller?.delegate = self // Note: moved this above the let guard
    guard let controller else { return assertionFailure() }
    controller.modalPresentationStyle = .overFullScreen
    present(controller, animated: false)

However, that's just being picky, so LGTM

I see where you're coming from! I made the change so I avoid enforcing the Onboarding protocol being implementable only by UIViewControllers. 👍