Animate the multirow section

[kjellr]

PR Summary:

Adds fade in on scroll animation to the Multirow section.

Why are these changes introduced?

Closes #2508.

What approach did you take?

Replicated animations from the original mockups in #2141

Visual impact on existing themes

Will animate Multirow sections on scroll, when "Reveal sections on scroll" is enabled.

multirow.mp4

Testing steps/scenarios

• Ensure "Reveal sections on scroll" is checked within Theme Settings > Animations.
• Add a Multirow section
• Add/remove blocks and adjust settings. Ensure things continue to animate in smoothly.

Demo links

• Store
• Editor

Checklist

• Added PR summary for release notes
• Requested review from UX (Only for changes that are affecting the experience or perceivable visual details)
• Created a ticket for the help.shopify.com documentation team about updates to theme settings. (Internal-only task)
• Followed theme code principles
• Linted with Theme Check
• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility

[metamoni]

Works well for me! 👍