code reformatting and adding const everywhere

lib/config/themes.dart

@@ -14,7 +14,7 @@ class AppThemes {
       default:
         return ThemeData(primarySwatch: Colors.deepPurple);
     }
-  }  
+  }
 
   static ThemeData getDarkTheme(ThemeType type) {
     switch (type) {
@@ -29,4 +29,5 @@ class AppThemes {
         return ThemeData.dark().copyWith(primaryColor: Colors.deepPurple);
     }
   }
-}
+}
+