lib/route: Declare no side effects (#37228)

Declares no sideEffects from the lib/route module.

https://webpack.js.org/guides/tree-shaking/#mark-the-file-as-side-effect-free

Author: sirreal

client/lib/route/package.json

@@ -0,0 +1,3 @@
+{
+	"sideEffects": false
+}