Refactor: Remove radio button for single active gateway

[pauloiankoski]

Resolves GIVE-545

Description

Currently, even when there is only one payment gateway option in the donation form, the radio button is shown. This does not make much sense in that situation since you cannot switch to any other method.

This pull request adds CSS styles to hide the radio button when the payment gateway is the only one in the list.

Affects

Gateways list

Visuals

Before

After

After but having more than 1 option

Testing Instructions

1. Configure more than one payment method in Settings.
2. Open a form and confirm that all options have radio buttons.
3. Re-configure the payment methods to have only one active.
4. Open the form and confirm that when there is only one option, no radio button is shown.

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

[jdghinson]

Looks good!

[JoshuaHungDinh]

That's a clever use of pseudo-class selectors. This is G2G!

[rickalday]

Passed manual QA tests.