[MOO-2184] Migrate to FlashList

[MxKevinBeqo]

Checklist

• Contains unit tests ✅
• Contains breaking changes ✅
• Compatible with: MX 11
• Did you update version and changelog? ✅
• PR title properly formatted ([XX-000]: description)? ✅
• Works in Android ✅
• Works in iOS ✅
• Works in Tablet ✅

Feature specific

• Comply with designs ✅
• Comply with PM's requirements ✅

This PR contains

• Bug fix
• Feature
• Refactor
• Documentation
• Other (describe): Migration of component - new depdendency

What is the purpose of this PR?

This PR migrates from using the FlastList component to the shopify/flash-list for the respective widgets who used FlatList.

What should be covered while testing?

Existing tests related to the Gallery and IntroScreen widgets.