Fix ModalView Overlay & Integrate AddPayMethod Flow

[leoAshu]

🚀 Summary

This PR fixes a ModalView bug to ensure it properly overlays the StatusBar, AppBar, and NavBar.

Additionally, it integrates the AddPayMethod flow into a modal, allowing users to add new payment methods without navigating away from the current screen.

🧩 Related Issues / Tasks

N/A

🛠️ Type of Change

• 🐞 Bug fix
• ✨ New feature
• 🧨 Breaking change
• 🔨 Enhancement/Refactor
• 📝 Documentation
• 📜 Other (please describe):

✅ Checklist

• The code is formatted with Prettier (npm run format or npx prettier --write .)
• PR references a linked Issue or Task number
• Tested on both iOS and Android devices/emulators
• No unnecessary logs or commented-out code
• UI changes, if any, have been reviewed visually
• All tests are passing (if applicable)
• Added or updated documentation where necessary

📸 Screenshots / Videos (UI changes only)

N/A

🧪 Test Plan

• Verified ModalView overlays StatusBar, AppBar, and NavBar correctly on AddPayMethod screen.
• Tested NewPayMethod modal for proper display, input, and submission flows.
• Confirmed compatibility with both light and dark themes.
• Ensured no regressions in navigation or modal-related UI elements.