Move Polling to above slides/webcams and change swapLayout constraints. Closes #5359

...luebutton-html5/imports/ui/components/media/component.jsx

...luebutton-html5/imports/ui/components/media/container.jsx

bigbluebutton-html5/imports/ui/components/media/service.js

bigbluebutton-html5/imports/ui/components/media/styles.scss

...ebutton-html5/imports/ui/components/polling/component.jsx

...luebutton-html5/imports/ui/components/polling/styles.scss

...on-html5/imports/ui/components/presentation/component.jsx