Issue #3440077 by jwilson3, dburiak, paraderojether, mortona2k, mandclu: Support new upload validator syntax from D10.2+

Replace SVG field upload validator syntax with the new one introduced in Drupal 10.2

Closes #3440077

src/Plugin/Field/FieldWidget/SvgImageFieldWidget.php

@@ -157,7 +157,25 @@ class SvgImageFieldWidget extends FileWidget {
     $element = parent::formElement($items, $delta, $element, $form, $form_state);
 
     $field_settings = $this->getFieldSettings();
-    $element['#upload_validators']['file_validate_extensions'][0] = 'svg';
+
+    if (!class_exists(DeprecationHelper::class)) {
+      $element['#upload_validators']['file_validate_extensions'][0] = 'svg';
+    }
+    else {
+      DeprecationHelper::backwardsCompatibleCall(
+        \Drupal::VERSION,
+        '10.2',
+        static function () use (&$element) {
+          $element['#upload_validators']['FileExtension'] = [
+            'extensions' => 'svg',
+          ];
+        },
+        static function () use (&$element) {
+          $element['#upload_validators']['file_validate_extensions'][0] = 'svg';
+        }
+      );
+    }
+
     $element['#upload_validators']['svg_image_field_validate_mime_type'] = [];
 
     // Add properties needed by process() method.