ENG-3769: Fix a11y issue on draft registration pages (#2199)

## Purpose

Fix a11y of an SVG icon on draft registration pages

## Summary of Changes

- Changed @ariaHidden to ensures the SVG icon is not hidden.
- Added aria-label.

Co-authored-by: Uditi Mehta <uditimehta@COSs-MacBook-Pro.local>

lib/osf-components/addon/components/registries/schema-block-renderer/helper-text-icon/template.hbs

@@ -5,7 +5,8 @@
             tabindex='0'
             id={{id}}
             @icon='question-circle'
-            @ariaHidden={{false}}
+            aria-hidden='false'
+            aria-label={{this.helpText}}
             ...attributes
         />
         <EmberPopover