fix: Duration in LottieRenderer rounds down milliseconds (#2808)

Duration in LottieRenderer rounds down milliseconds and causes two problems:

    Speeds up when rendering a Lottie animation that duration is non-integer seconds.
    When rendering Lottie animation that duration shorter than one second, duration of the animation will detect as zero seconds and cause the hole game freeze at a single frame.

packages/flame_lottie/lib/src/lottie_renderer.dart

@@ -35,7 +35,7 @@ class LottieRenderer {
           ..enableMergePaths = enableMergePaths ?? false,
         _controller = controller ??
             EffectController(
-              duration: duration ?? composition.duration.inSeconds.toDouble(),
+              duration: duration ?? composition.duration.inMilliseconds / 1000,
               infinite: repeating ?? false,
             ) {
     size.addListener(() {