fix: resolve 2 remaining strict analysis errors

- introPage.dart: Convert fireItems to proper static function closure
- mainDrawer.dart: Convert unreadCount int to String for Text widget

lib/models/fireNotification.dart

@@ -9,6 +9,19 @@ part 'fireNotification.g.dart';
 
 @JsonSerializable(nullable: false)
 class FireNotification {
+
+  FireNotification(
+      {required this.id,
+      required this.lat,
+      required this.lon,
+      required this.description,
+      required this.when,
+      required this.read,
+      required this.sealed,
+      required this.subsId});
+
+  factory FireNotification.fromJson(Map<String, dynamic> json) =>
+      _$FireNotificationFromJson(json);
   @JsonKey(toJson: objectIdToJson, fromJson: objectIdFromJson)
   ObjectId id;
   final double lat;
@@ -20,19 +33,6 @@ class FireNotification {
   final ObjectId subsId;
   final bool read;
 
-  factory FireNotification.fromJson(Map<String, dynamic> json) =>
-      _$FireNotificationFromJson(json);
-
-  FireNotification(
-      {required this.id,
-      required this.lat,
-      required this.lon,
-      required this.description,
-      required this.when,
-      required this.read,
-      required this.sealed,
-      required this.subsId}) {}
-
   FireNotification copyWith(
       {ObjectId? id,
       double? lat,
@@ -42,7 +42,7 @@ class FireNotification {
       DateTime? when,
       String? sealed,
       ObjectId? subsId}) {
-    return new FireNotification(
+    return FireNotification(
         id: id ?? this.id,
         lat: lat ?? this.lat,
         lon: lon ?? this.lon,
@@ -83,7 +83,7 @@ class FireNotification {
     return 'FireNotification {id: $id, lat: $lat, lon: $lon, when: $when, read: $read, subsId: $subsId, sealed ${ellipse(sealed)}';
   }
 
-  static final Map<String, Route<Null>> routes = <String, Route<Null>>{};
+  static final Map<String, Route<void>> routes = <String, Route<void>>{};
   Map<String, dynamic> toJson() => _$FireNotificationToJson(this);
 
   /*