audit: remove redundant check

Co-authored-by: Rylan Polster <rslpolster@gmail.com>

Library/Homebrew/dev-cmd/audit.rb

@@ -399,7 +399,7 @@ module Homebrew
 
         github_license = GitHub.get_repo_license(user, repo)
         return unless github_license
-        return if github_license && (licenses + ["NOASSERTION"]).include?(github_license)
+        return if (licenses + ["NOASSERTION"]).include?(github_license)
         return if PERMITTED_LICENSE_MISMATCHES[github_license]&.any? { |license| licenses.include? license }
         return if PERMITTED_FORMULA_LICENSE_MISMATCHES[formula.name] == formula.version