TF-105 [BUG] Fix no subject should show empty instead of null

lib/features/composer/presentation/composer_controller.dart

@@ -129,7 +129,7 @@ class ComposerController extends BaseController {
         && composerArguments.value?.presentationEmail != null
         && Get.context != null) {
       final subject = '${composerArguments.value!.emailActionType.prefixSubjectComposer(Get.context!)} '
-          '${composerArguments.value!.presentationEmail?.subject}';
+          '${composerArguments.value!.presentationEmail?.getEmailTitle()}';
       setSubjectEmail(subject);
       subjectEmailInputController.text = subject;
     }

lib/features/email/presentation/email_view.dart

@@ -117,7 +117,7 @@ class EmailView extends GetView {
     return Padding(
       padding: EdgeInsets.only(left: 8, top: 4, bottom: 16),
       child: Text(
-          '${emailController.mailboxDashBoardController.selectedEmail.value?.subject}',
+          '${emailController.mailboxDashBoardController.selectedEmail.value?.getEmailTitle()}',
           style: TextStyle(fontSize: 18, color: AppColor.mailboxTextColor, fontWeight: FontWeight.w500)
       ));
   }

model/lib/email/presentation_email.dart

@@ -44,12 +44,7 @@ class PresentationEmail with EquatableMixin {
     }
   );
 
-  String getSenderName() {
-    if (from != null && from!.isNotEmpty) {
-      return from!.first.asString();
-    }
-    return '';
-  }
+  String getSenderName() => from?.first.asString() ?? '';
 
   String getAvatarText() {
     if (getSenderName().isNotEmpty) {
@@ -58,9 +53,9 @@ class PresentationEmail with EquatableMixin {
     return '';
   }
 
-  String getEmailTitle() => subject != null ? subject! : '';
+  String getEmailTitle() => subject ?? '';
 
-  String getPartialContent() => preview != null ? preview! : '';
+  String getPartialContent() => preview ?? '';
 
   bool isUnReadEmail() => !(keywords?.containsKey(KeyWordIdentifier.emailSeen) == true);
 

model/lib/extensions/email_address_extension.dart

@@ -28,9 +28,9 @@ extension EmailAddressExtension on EmailAddress {
     return '';
   }
 
-  String get emailAddress => email != null ? email! : '';
+  String get emailAddress => email ?? '';
 
-  String get displayName => name != null ? name! : '';
+  String get displayName => name ?? '';
 
   EmailAddressCache toEmailAddressCache() => EmailAddressCache(displayName, emailAddress);
 }