MDL-64175 atto_media: update advanced settings

Some OS, such as Ubuntu, are slightly changing the audio attributes,
from <audio attribute1="true"> to <audio attribute1>.
This patch is for reviewing this piece of code and covering both cases.

lib/editor/atto/plugins/media/yui/build/moodle-atto_media-button/moodle-atto_media-button-debug.js

@@ -714,7 +714,9 @@ Y.namespace('M.atto_media').Button = Y.Base.create('button', Y.M.editor_atto.Edi
      */
     _getMediumProperties: function(medium) {
         var boolAttr = function(elem, attr) {
-            return elem.getAttribute(attr) ? true : false;
+            // As explained in MDL-64175, some OS (like Ubuntu), are removing the value for these attributes.
+            // So in order to check if attr="true", we need to check if the attribute exists and if the value is empty or true.
+            return (elem.hasAttribute(attr) && (elem.getAttribute(attr) || elem.getAttribute(attr) === ''));
         };
 
         var tracks = {

lib/editor/atto/plugins/media/yui/build/moodle-atto_media-button/moodle-atto_media-button.js

@@ -714,7 +714,9 @@ Y.namespace('M.atto_media').Button = Y.Base.create('button', Y.M.editor_atto.Edi
      */
     _getMediumProperties: function(medium) {
         var boolAttr = function(elem, attr) {
-            return elem.getAttribute(attr) ? true : false;
+            // As explained in MDL-64175, some OS (like Ubuntu), are removing the value for these attributes.
+            // So in order to check if attr="true", we need to check if the attribute exists and if the value is empty or true.
+            return (elem.hasAttribute(attr) && (elem.getAttribute(attr) || elem.getAttribute(attr) === ''));
         };
 
         var tracks = {

lib/editor/atto/plugins/media/yui/src/button/js/button.js

@@ -712,7 +712,9 @@ Y.namespace('M.atto_media').Button = Y.Base.create('button', Y.M.editor_atto.Edi
      */
     _getMediumProperties: function(medium) {
         var boolAttr = function(elem, attr) {
-            return elem.getAttribute(attr) ? true : false;
+            // As explained in MDL-64175, some OS (like Ubuntu), are removing the value for these attributes.
+            // So in order to check if attr="true", we need to check if the attribute exists and if the value is empty or true.
+            return (elem.hasAttribute(attr) && (elem.getAttribute(attr) || elem.getAttribute(attr) === ''));
         };
 
         var tracks = {