Add video caption track if captionFile is available (#25997)

GitOrigin-RevId: fefcce66fe573385dfec34cc0f8697220fe418a3

services/web/config/settings.defaults.js

@@ -893,6 +893,7 @@ module.exports = {
           'figcaption',
           'span',
           'source',
+          'track',
           'video',
           'del',
         ],
@@ -943,6 +944,7 @@ module.exports = {
             'style',
           ],
           tr: ['class'],
+          track: ['src', 'kind', 'srcLang', 'label'],
           video: ['alt', 'class', 'controls', 'height', 'width'],
         },
       },