TF-1710 Add CountOfEmails widget

(cherry picked from commit 5ab596a6a9433b57ae20c80fd22f2e7f70912e46)

lib/features/mailbox/presentation/styles/count_of_emails_styles.dart

@@ -0,0 +1,8 @@
+
+import 'package:flutter/material.dart';
+
+class CountOfEmailsStyles {
+  static const Color textColor = Colors.black;
+  static const double textSize = 13;
+  static const FontWeight textFontWeight = FontWeight.w400;
+}