Fix: prevent Stripe Payment Element from rendering when amount is zero

[jonwaldstein]

Resolves GIVE-509

Description

This prevents the Stripe Payment Element from rendering when the donation amount is zero by adding a conditional before loading the fields.

Affects

Stripe payment element gateways

Visuals

Before:

After

Testing Instructions

• create a v3 form
• specify 0 for the amount
• click on stripe payment element

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

[github-actions]

This PR is stale because it has been open 45 days with no activity. Stale PRs will NOT be automatically closed.

[jonwaldstein]

Closing for now:

I started working on this for Stripe but quickly realized the nuances become a weird experience. When 0 is entered we can display a message within the gateway but you can still technically submit the form and receive an error. Furthermore, Stripe uses the amount value, while events are not included in this value.

[rickalday]

Passed manual QA tests.