Add missing protobuf dependency (#36394)

packages/flutter_tools/BUILD.gn

diff --git a/packages/flutter_tools/BUILD.gn b/packages/flutter_tools/BUILD.gn
index 79988db..359c369 100644
--- a/packages/flutter_tools/BUILD.gn
+++ b/packages/flutter_tools/BUILD.gn
@@ -39,6 +39,7 @@
     "//third_party/dart-pkg/pub/path",
     "//third_party/dart-pkg/pub/platform",
     "//third_party/dart-pkg/pub/process",
+    "//third_party/dart-pkg/pub/protobuf",
     "//third_party/dart-pkg/pub/quiver",
     "//third_party/dart-pkg/pub/shelf_packages_handler",
     "//third_party/dart-pkg/pub/shelf_static",
@@ -46,7 +47,7 @@
     "//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/webkit_inspection_protocol",
+    "//third_party/dart-pkg/pub/webkit_inspection_protocol",
     "//third_party/dart-pkg/pub/xml",
     "//third_party/dart-pkg/pub/yaml",
     "//third_party/dart-pkg/pub/node_preamble",