Roll Fuchsia Linux SDK from -p5aJwkrm... to k8lUt8ibj... (#34444)

https://dart.googlesource.com/external/github.com/flutter/engine/+/51dc113c3f0f7549d3528c7e54f24ce3be4aacde
diff --git a/commits.json b/commits.json
index 5865808..d6cf78c 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
-  "external/github.com/flutter/engine":"c5e54626ff6881ce8991f7312ae72cbc9b7c9231",
+  "external/github.com/flutter/engine":"51dc113c3f0f7549d3528c7e54f24ce3be4aacde",
   "external/github.com/flutter/flutter":"924d1740869dee8b5dbe795a430246c45f582e23",
   "sdk":"2cd9404f2692d7e44d51041e42015f22e29180fe"
 }
\ No newline at end of file