Issue #3499625 by just_like_good_vibes: Introduce a new source to get access to the current "i-th" referenced entity from a field entity reference in the context of component per item field formatter

Closes #3499625

src/Element/ComponentElementBuilder.php

@@ -40,7 +40,7 @@ class ComponentElementBuilder implements TrustedCallbackInterface {
    * Build component data provided to the SDC element.
    */
   public function build(array $element): array {
-    if (!isset($element['#ui_patterns'])) {
+    if (!isset($element['#ui_patterns']) || !isset($element['#component'])) {
       return $element;
     }
     $configuration = $element['#ui_patterns'];