b8473cdee use correct no-download-badge (flutter/engine#7735) (#27669)

https://github.com/flutter/engine/compare/b0370c13c302...b8473cdee13d

git log b0370c13c302bc747f0cb3736a3a79e79ae4f7cd..b8473cdee13d4739afda6b171f4c84280584ab98 --no-merges --oneline
b8473cdee use correct no-download-badge (flutter/engine#7735)

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bin/internal/engine.version

-b0370c13c302bc747f0cb3736a3a79e79ae4f7cd
+b8473cdee13d4739afda6b171f4c84280584ab98