[Due for payment 2025-12-30] [Custom Columns][Release 4] Add exchangeRate column to Search results

[luacmartins]

1. Add the exchangeRate column to this array
2. Add the exchangeRate columns to this function, with default to false
3. Create a new component ExchangeRateCell, following this pattern
   1. This component will compute the exchange rate by dividing convertedAmount / originalAmount
   2. Display the value and the originalCurrency / reportCurrency
4. Add a ExchangeRateCell component for the originalAmount column and Text cell for the originalCurrency here (follow the order here)
5. Add automated tests here

Parent issue: https://github.com/Expensify/Expensify/issues/566674

[ChavdaSachin]

I would like to work on this feature in case it is open for external contributors, details are mentioned OP.

[JS00001]

This is being worked on this week