Roll Flutter Engine from 2471f430ff4b to bb7b7006f4a3 (2 revisions) (#119655)

* 32c157e34 [web] Remove unused test helper: expectPageHtml (flutter/engine#39287)

* bb7b7006f Unblock Skia roll by including SkSurface header (flutter/engine#39295)
diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index c6e4dd7..1044ee3 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-2471f430ff4bf3012b149762375b7cf921596a5b
+bb7b7006f4a33a0a5b17d2acfe1eade3b82d949b