TF-2528 Add integration test for search email with sort by sender nam…e ascending

core/lib/domain/extensions/list_datetime_extension.dart

@@ -0,0 +1,21 @@
+
+extension ListDateTimeExtension on List<DateTime> {
+
+  bool isSortedByMostRecent() {
+    for (int i = 0; i < length - 1; i++) {
+      if (this[i].isBefore(this[i + 1])) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  bool isSortedByOldestFirst() {
+    for (int i = 0; i < length - 1; i++) {
+      if (this[i].isAfter(this[i + 1])) {
+        return false;
+      }
+    }
+    return true;
+  }
+}