feat(entity_details): add theme data to EntityDetailsLoadRequested event

- Add 'theme' parameter to EntityDetailsLoadRequested constructor
- Include ThemeData in EntityDetailsLoadRequested props
- Update documentation for new theme parameter

Author: fulleni

lib/entity_details/bloc/entity_details_event.dart

@@ -14,6 +14,7 @@ abstract class EntityDetailsEvent extends Equatable {
 /// or an [entityId] and its corresponding [contentType].
 class EntityDetailsLoadRequested extends EntityDetailsEvent {
   const EntityDetailsLoadRequested({
+    required this.theme,
     this.entityId,
     this.contentType,
     this.entity,
@@ -31,6 +32,9 @@ class EntityDetailsLoadRequested extends EntityDetailsEvent {
   /// The full entity object, if already available.
   final FeedItem? entity;
 
+  /// The current theme data, required for ad injection.
+  final ThemeData theme;
+
   @override
   List<Object?> get props => [entityId, contentType, entity];
 }