Restore logic for Utils#element_text

In this commit I'm putting the tests back the way they were and
restoring the logic in the Utils.element_text.

Instead I'm applying the change that @brianswko suggested at the start
of #443

This still allows for my new test to pass.

Author: netikular

lib/onelogin/ruby-saml/response.rb

@@ -322,7 +322,7 @@ def destination
       def audiences
         @audiences ||= begin
           nodes = xpath_from_signed_assertion('/a:Conditions/a:AudienceRestriction/a:Audience')
-          nodes.map { |node| Utils.element_text(node) }.compact
+          nodes.map { |node| Utils.element_text(node) }.reject(&:empty?)
         end
       end
 

lib/onelogin/ruby-saml/utils.rb

@@ -286,7 +286,7 @@ def self.original_uri_match?(destination_url, settings_url)
       # that there all children other than text nodes can be ignored (e.g. comments). If nil is
       # passed, nil will be returned.
       def self.element_text(element)
-        element.texts.join if element && !element.texts.empty?
+        element.texts.join if element
       end
     end
   end

test/response_test.rb

@@ -1137,12 +1137,12 @@ class RubySamlTest < Minitest::Test
 
         it "return multiple values including nil and empty string" do
           response = OneLogin::RubySaml::Response.new(fixture(:response_with_multiple_attribute_values))
-          assert_equal [nil, "valuePresent", nil, nil], response.attributes.multi(:attribute_with_nils_and_empty_strings)
+          assert_equal ["", "valuePresent", nil, nil], response.attributes.multi(:attribute_with_nils_and_empty_strings)
         end
 
         it "return multiple values from [] when not in compatibility mode off" do
           OneLogin::RubySaml::Attributes.single_value_compatibility = false
-          assert_equal [nil, "valuePresent", nil, nil], response_multiple_attr_values.attributes[:attribute_with_nils_and_empty_strings]
+          assert_equal ["", "valuePresent", nil, nil], response_multiple_attr_values.attributes[:attribute_with_nils_and_empty_strings]
           OneLogin::RubySaml::Attributes.single_value_compatibility = true
         end