Feature: hide gateways when donation amount is zero

[jonwaldstein]

Resolves #

Description

This hides gateways when the donation amount is zero. This is primarily a precautionary measure to avoid errors with gateways as there is no reason to display a gateway when there is no amount. It's purely a visual update to prevent gateways from rendering in this scenario. It does not actually prevent the form from submitting, which will let the validation framework take over.

Related: #7515

In the future, our forms may be more flexible in creating something that does not equate to an amount. However, at this time all our gateways require an amount.

Affects

The v3 donation form gateway options

Visuals

Testing Instructions

Enter $0 in the custom amount field and scroll to the gateway options, you should be presented with a message instead of gateways.

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