fix(SUP-12799): fix audio selector icon drops down when clicked (#3627)
fix(SUP-12799): fix audio selector icon drops down when clicked (#3627)

#### Select audio button (Multiple audio tracks) drops down when selected
* Add the `dropdown-menu` class to the menu element
FlixMaster/mwEmbed,kaltura/mwEmbed,FlixMaster/mwEmbed,kaltura/mwEmbed,FlixMaster/mwEmbed,kaltura/mwEmbed,kaltura/mwEmbed,FlixMaster/mwEmbed