fix:🐛️ correct formatting and improve assertions for RiveArtboardSource usage (#63)

Author: apurva010

lib/core/source.dart

@@ -87,7 +87,7 @@ final class BytesSource extends Source {
 }
 
 /// Provides a pre-loaded Rive artboard instance for the splash screen
-final class RiveArtboardSource extends Source{
+final class RiveArtboardSource extends Source {
   /// Provides a pre-loaded Rive artboard instance for the splash screen
   RiveArtboardSource(this.artboard);
 

lib/core/splash_master.dart

@@ -41,7 +41,8 @@ class SplashMaster extends StatefulWidget {
   })  : splashMediaType = SplashMediaType.lottie,
         videoConfig = null,
         riveConfig = null,
-        assert(source is! RiveArtboardSource,
+        assert(
+          source is! RiveArtboardSource,
           "RiveArtboardSource is not supported for lottie splash",
         );
 
@@ -57,7 +58,8 @@ class SplashMaster extends StatefulWidget {
   })  : splashMediaType = SplashMediaType.video,
         lottieConfig = null,
         riveConfig = null,
-        assert(source is! RiveArtboardSource,
+        assert(
+          source is! RiveArtboardSource,
           "RiveArtboardSource is not supported for video splash",
         );