Fix Demo App Funding Source

[jaxdesmarais]

Reason for changes

The funding source tags were flipped for PayPal Pay Later and PayPal Credit in the Demo app.

Summary of changes

• Associate PayPalWebCheckoutFundingSource with the correct tags/buttons - clicking on the expected picker button will now lead to the expected PayPal Pay Later or PayPal Credit flow and button

Visuals

Before	After

Checklist

• ~[ ] Added a changelog entry~

Authors

• @jaxdesmarais

[KunJeongPark]

Thank you!