TF-4179 Sort label list by alphabet

labels/lib/extensions/label_extension.dart

@@ -39,4 +39,10 @@ extension LabelExtension on Label {
       color: color ?? this.color,
     );
   }
+
+  int compareAlphabetically(Label otherLabel) {
+    return safeDisplayName
+        .toLowerCase()
+        .compareTo(otherLabel.safeDisplayName.toLowerCase());
+  }
 }

labels/lib/extensions/list_label_extension.dart

@@ -0,0 +1,12 @@
+import 'package:collection/collection.dart';
+import 'package:labels/extensions/label_extension.dart';
+import 'package:labels/model/label.dart';
+
+extension ListLabelExtension on List<Label> {
+  void sortByAlphabetically() {
+    sortByCompare<Label>(
+      (label) => label,
+      (label, otherLabel) => label.compareAlphabetically(otherLabel),
+    );
+  }
+}

labels/lib/labels.dart

@@ -11,3 +11,4 @@ export 'package:labels/method/changes/changes_label_method.dart';
 export 'package:labels/method/changes/changes_label_response.dart';
 
 export 'package:labels/extensions/label_extension.dart';
+export 'package:labels/extensions/list_label_extension.dart';