:mrs_claus: Christmas release! :santa:

This is a patch release with:

• a bug related to Firefox
• a bug if you use data-disable-preview

List of changes:

• Fix medium-editor-insert plugin css fixes on beagle theme #1361
• Update jsDelivr links #1366 & #1367
• Fix Firefox console warning causing issues #1370
• Do not check only for null targets or it will fail when it's undefined. #1373
• Fix crash when 'extensions' in 'isElementDescendantOfExtension' is undefined #1362
• Fix Jasmine Unit Test errors #1385
• Fix null error on pastedPlain.split #1397
• Fix broken browser tests #1396