Feature: Scroll Stripe checkout modal into view for Legacy + Multistep forms

[JoshuaHungDinh]

Resolves #6788

Description

This PR adds functionality to scroll the Stripe checkout modal into view when the user clicks the purchase button. The checkout modal will now be visible to the user, regardless of their screen size. This fix currently only works for legacy & classic templates.

Affects

Stripe checkout modal

Visuals

Testing Instructions

• Create a form and set Stripe Checkout as a payment option.
• Begin the donation process on a mobile device, a long donation form, or with altered viewports on a desktop.
• Fill out the form until you reach the second to last step before payment.
• Click on the "Donate Now" button.
• The Stripe modal should scroll into view.

• 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

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[JasonTheAdams]

Looks good, @JoshuaHungDinh! This should work. I just notice a super minor formatting thing.

[github-actions]

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

[jonwaldstein]

@JoshuaHungDinh what's the status of this?

[JoshuaHungDinh]

@jonwaldstein So there was some back and forth on the PR because it would only scroll the stripe modals for Legacy and Multistep form. It would not work on classic. We are left with two options. Either merge a partial fix or close it out. Heres the last conversations. I think the verdict was a little unclear due to how much time had passed. What do you think? https://app.asana.com/0/1203193833018151/1204508757292153

[jonwaldstein]

@JoshuaHungDinh gotchya, I would go with partial fix and change the PR title/scope to state that it's just for legacy & multistep. Classic template is still the least used one so at least this would be fixed for folks using the other templates and we can circle back if need be.