Fixes Exception by changing slide Animation in Intro-Screen

lib/ui/screens/introduction_screen.dart

@@ -157,7 +157,7 @@ class _IntroScreenState extends State<IntroScreen> {
               color: _appSetting.primaryColor,
               fontSize: _appSetting.bodyTextFontSize,
               fontWeight: FontWeight.w700)),
-      curve: Curves.fastLinearToSlowEaseIn,
+      curve: Curves.easeIn,
       controlsMargin: const EdgeInsets.all(6),
       controlsPadding: kIsWeb
           ? const EdgeInsets.all(12.0)