deps: Upgrade Flutter to 3.27.0-1.0.pre.518

This pulls in:
  flutter/flutter@dca37ad
which slightly changed the generated header for localization files.

Author: rajveermalviya

pubspec.lock

@@ -1368,5 +1368,5 @@ packages:
     source: path
     version: "0.0.1"
 sdks:
-  dart: ">=3.7.0-123.0.dev <4.0.0"
-  flutter: ">=3.27.0-1.0.pre.443"
+  dart: ">=3.7.0-140.0.dev <4.0.0"
+  flutter: ">=3.27.0-1.0.pre.518"

pubspec.yaml

@@ -14,8 +14,8 @@ environment:
   # We use a recent version of Flutter from its main channel, and
   # the corresponding recent version of the Dart SDK.
   # Feel free to update these regularly; see README.md for instructions.
-  sdk: '>=3.7.0-123.0.dev <4.0.0'
-  flutter: '>=3.27.0-1.0.pre.443'
+  sdk: '>=3.7.0-140.0.dev <4.0.0'
+  flutter: '>=3.27.0-1.0.pre.518'
 
 # To update dependencies, see instructions in README.md.
 dependencies: