Refactor Post Advert Form State & UI Enhancements

[leoAshu]

🚀 Summary

This PR refactors and enhances the Post Advert flow to improve maintainability and UI consistency.

• Refactors multiple state variables into a single formData state for the Post Advert index screen, simplifying state management.
• Adds an option title to the ToggleButton component for better clarity in selections.
• Fixes PriceType field styling for light theme to ensure visual consistency.

🧩 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 that formData correctly holds all post advert fields.
• Confirmed ToggleButton displays option titles across screens.
• Ensured PriceType field styling looks correct in both light and dark themes.