refactor: Use default systemUiOverlayStyle

lib/config/themes.dart

@@ -99,11 +99,7 @@ abstract class FluffyThemes {
     appBarTheme: AppBarTheme(
       brightness: Brightness.light,
       color: Colors.white,
-      systemOverlayStyle: SystemUiOverlayStyle(
+      systemOverlayStyle: SystemUiOverlayStyle.dark,
-        systemNavigationBarColor: Colors.white,
-        systemNavigationBarIconBrightness: Brightness.dark,
-        statusBarColor: Colors.transparent,
-      ),
       textTheme: TextTheme(
         headline6: TextStyle(
           color: Colors.black,
@@ -182,11 +178,7 @@ abstract class FluffyThemes {
     appBarTheme: AppBarTheme(
       brightness: Brightness.dark,
       color: Color(0xff1D1D1D),
-      systemOverlayStyle: SystemUiOverlayStyle(
+      systemOverlayStyle: SystemUiOverlayStyle.light,
-        systemNavigationBarColor: Colors.black,
-        systemNavigationBarIconBrightness: Brightness.light,
-        statusBarColor: Colors.transparent,
-      ),
       textTheme: TextTheme(
         headline6: TextStyle(
           color: Colors.white,