Roll engine 5194919e1309..56c16154eada (3 commits) (#28686)

https://github.com/flutter/engine/compare/5194919e1309...56c16154eada

git log 5194919e130917d29ac15f0ac7f52ea94d1a4d67..56c16154eadada5f77c57ddca39a86c5e30c5768 --no-merges --oneline
56c16154e Android Embedding PR 9: Introduce an AndroidTouchProcessor to convert MotionEvents to Flutter touch data. (flutter/engine#7947)
a1d84996d Fix spelling errors in dartdocs (flutter/engine#7997)
6bc9c3d17 Roll src/third_party/dart 40bab34fbd..7c70ab1817 (35 commits)

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bin/internal/engine.version

-5194919e130917d29ac15f0ac7f52ea94d1a4d67
+56c16154eadada5f77c57ddca39a86c5e30c5768