fix: u-image-zoom validation

[wesleyboar]

Overview

Fix validation logic error in "Zoom image" templates.

Related

• fixes feat: support core-styles u-image-zoom #968

Changes

• fixes parent plugin comparison
• deletes unused variables

Testing

1. Open https://dev.cep.tacc.utexas.edu/test/image-picture-block/?edit (or similar test page).
2. Edit and save Image at "Template: zoom_effect • External image: 🚫 • Within a Link: ✅": "[in a Link] Attrs"
   • Save should have no validation error.
   • Image should zoom on hover.
3. Edit and save Image at "Template: zoom_effect_no_link_to_ext_image • External image: 🚫 • Within a Link: ✅": "[in a Link] Attrs"
   • Save should have no validation error.
   • Image should zoom on hover.

UI

Template: zoom_effect • External image: 🚫 • Within a Link: ✅

zoom_effect.BEFORE.mov

zoom_effect_no_link_to_ext_image.AFTER.mov

Template: zoom_effect_no_link_to_ext_image • External image: ✅ • Within a Link: ✅

zoom_effect_no_link_to_ext_image.BEFORE.mov

zoom_effect.AFTER.mov