fix(grunt-utils): ensure special inline CSS works when `angular` is not a global

The build includes a little script to angular.js, which adds some CSS styles to
the page to support things like ngCloak. This script checks that angular is
not in CSP mode, but before this fix assumed that angular would be in the global
scope.

This commit, references `window.angular` instead of just `angular` because when
running angular in an environment where the top-level scope is not the window
(nodejs for example), we angular is actually a property of `window`.

Closes #7176