TF-2068 Fix calendar banner widget is gray bar

(cherry picked from commit 69998d944921d045c2c26acf0c66e01feb79112d)

model/lib/extensions/list_email_address_extension.dart

@@ -8,6 +8,8 @@ extension ListEmailAddressExtension on Set<EmailAddress>? {
 
   List<EmailAddress> asList() => this != null ? this!.toList() : List.empty();
 
+  Set<EmailAddress> asSet() => this ?? {};
+
   List<String> emailAddressToListString({ExpandMode expandMode = ExpandMode.EXPAND, int limitAddress = 1, bool isFullEmailAddress = false}) {
     if (this != null) {
       if (expandMode == ExpandMode.EXPAND) {

model/lib/extensions/presentation_email_extension.dart

@@ -34,6 +34,8 @@ extension PresentationEmailExtension on PresentationEmail {
     return '';
   }
 
+  Set<EmailAddress> get listEmailAddressSender => from.asSet()..addAll(replyTo.asSet());
+
   PresentationEmail toggleSelect() {
     return PresentationEmail(
       id: this.id,