Fix: Hide donation form submit button to prevent errors with PayPal Commerce payment flow

[pauloiankoski]

Resolves GIVE-1097

Description

This PR addresses an issue where donors click the donation form’s submit button instead of PayPal’s “Pay Now” button when filling out credit card fields through PayPal Commerce. This causes an error, as PayPal cannot complete the transaction properly through the form’s submit button.

The solution hides the form’s submit button when PayPal Commerce is selected, ensuring donors interact only with PayPal’s button. The submit button is restored when switching to other gateways and PayPal Commerce fields component unmounts.

Affects

Visual Builder Forms

Visuals

Testing Instructions

1. Navigate to the donation form page.
2. Select “Donate with Credit Card” (PayPal Commerce) as the payment gateway.
3. Verify that the form’s submit button is hidden, ensuring only PayPal’s “Pay Now” button is available for interaction.
4. Change to a different payment gateway and verify that the submit button is visible again.
5. Repeat the process and ensure that switching between gateways consistently shows or hides the correct buttons.

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed

[JoshuaHungDinh]

Looks good!

[rickalday]

Passed manual QA tests.