Add ability to select distance unit

lib/components/dashboard/leaderboard_panel.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:mileograph_flutter/services/data_service.dart';
+import 'package:mileograph_flutter/services/distance_unit_service.dart';
 
 import 'package:provider/provider.dart';
 
@@ -9,6 +10,7 @@ class LeaderboardPanel extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final data = context.watch<DataService>();
+    final distanceUnits = context.watch<DistanceUnitService>();
     final leaderboard = data.homepageStats?.leaderboard ?? [];
     final textTheme = Theme.of(context).textTheme;
     if (data.isHomepageLoading && leaderboard.isEmpty) {
@@ -82,7 +84,10 @@ class LeaderboardPanel extends StatelessWidget {
                         ),
                       ),
                       trailing: Text(
-                        '${leaderboard[index].mileage.toStringAsFixed(1)} mi',
+                        distanceUnits.format(
+                          leaderboard[index].mileage,
+                          decimals: 1,
+                        ),
                         style: textTheme.labelLarge?.copyWith(
                           fontWeight: FontWeight.w700,
                         ),