cleanup: Remove license comment in proto build file (#1118)

The license comments aren't necessary anymore.

python/private/proto/BUILD

diff --git a/python/private/proto/BUILD b/python/private/proto/BUILD
index 139696c..971b354 100644
--- a/python/private/proto/BUILD
+++ b/python/private/proto/BUILD
@@ -17,7 +17,7 @@
 
 package(default_visibility = ["//visibility:public"])
 
-licenses(["notice"])  # Apache 2.0
+licenses(["notice"])
 
 filegroup(
     name = "distribution",