Fix a Xiaomi specific crash (#2061)

Fixes #2050
diff --git a/lottie/src/main/java/com/airbnb/lottie/animation/keyframe/BaseKeyframeAnimation.java b/lottie/src/main/java/com/airbnb/lottie/animation/keyframe/BaseKeyframeAnimation.java
index d9ca3bc..8f13143 100644
--- a/lottie/src/main/java/com/airbnb/lottie/animation/keyframe/BaseKeyframeAnimation.java
+++ b/lottie/src/main/java/com/airbnb/lottie/animation/keyframe/BaseKeyframeAnimation.java
@@ -101,7 +101,9 @@
    */
   protected float getInterpolatedCurrentKeyframeProgress() {
     Keyframe<K> keyframe = getCurrentKeyframe();
-    if (keyframe.isStatic()) {
+    // Keyframe should not be null here but there seems to be a Xiaomi Android 10 specific crash.
+    // https://github.com/airbnb/lottie-android/issues/2050
+    if (keyframe == null || keyframe.isStatic()) {
       return 0f;
     }
     //noinspection ConstantConditions