Remove out of date comment (#6314)

This was previously resolved.

Author: ryanwilson

FirebaseStorage.podspec

@@ -19,7 +19,6 @@ Firebase Storage provides robust, secure file uploads and downloads from Firebas
   s.ios.deployment_target = '8.0'
   s.osx.deployment_target = '10.11'
   s.tvos.deployment_target = '10.0'
-  # spec won't validate or push with FirebaseAuth as a test spec dependency.
   s.watchos.deployment_target = '6.0'
 
   s.cocoapods_version = '>= 1.4.0'