[NT-885] Landing page optimizely events

[Scollaco]

📲 What

• Adds Optimizely events to track when app enters in background and when the Get Started button on the Landing Page is tapped.

🤔 Why

Jira ticket .

🛠 How

• On the AppDelegateViewModel, added the tracking client to fire whenever applicationDidEnterBackgroundProperty.signal emits.
• On the LandingPageViewModel, added the tracking client to fire whenever ctaButtonTappedSignal emits.

👀 See

• N/A

✅ Acceptance criteria

• Launch the app and put in background. The App Closed event should appear on the logs.

On AppDelegateViewModel, add a return true below the shouldGoToLandingPage function signature. This will force the Landing Page to be presented:

• Once the Landing Page is presented, tap Get Started button. The Get Started Button Clicked event should appear on the logs.