ensure that fe server is always built with tool (#29768)

diff --git a/packages/flutter_tools/BUILD.gn b/packages/flutter_tools/BUILD.gn
index 2df1803..48b481d 100644
--- a/packages/flutter_tools/BUILD.gn
+++ b/packages/flutter_tools/BUILD.gn
@@ -253,4 +253,8 @@
   deps = [
     ":flutter_tools",
   ]
+
+  non_dart_deps = [
+    "//third_party/flutter/frontend_server:frontend_server_tool_snapshot($host_toolchain)",
+  ]
 }