add skottie to android bp

Change-Id: If858b0840d796557b8304933797aa47573a3588f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/551895
Auto-Submit: Jorge Betancourt <jmbetancourt@google.com>
Commit-Queue: Jorge Betancourt <jmbetancourt@google.com>
Reviewed-by: Florin Malita <fmalita@google.com>

gn/gn_to_bp.py

@@ -546,6 +546,7 @@ def generate_args(target_os, enable_gpu, renderengine = False):
     d['skia_use_fixed_gamma_text'] = 'true'
     d['skia_enable_fontmgr_custom_empty'] = 'true'
     d['skia_use_wuffs'] = 'true'
+    d['skia_enable_skottie'] = 'true'
 
   return d