[gn] Update flutter_tools GN build (#7592)

This package depends on package:process now.

packages/flutter_tools/BUILD.gn

@@ -25,12 +25,13 @@ dart_package("flutter_tools") {
     "//third_party/dart-pkg/pub/mustache",
     "//third_party/dart-pkg/pub/package_config",
     "//third_party/dart-pkg/pub/path",
+    "//third_party/dart-pkg/pub/process",
     "//third_party/dart-pkg/pub/pub_semver",
     "//third_party/dart-pkg/pub/stack_trace",
+    "//third_party/dart-pkg/pub/test",
     "//third_party/dart-pkg/pub/usage",
     "//third_party/dart-pkg/pub/web_socket_channel",
     "//third_party/dart-pkg/pub/xml",
     "//third_party/dart-pkg/pub/yaml",
-    "//third_party/dart-pkg/pub/test",
   ]
 }