fix duplicate css variables being loaded (improve imports)

...i/components/actions-bar/captions/reader-menu/styles.scss

...i/components/actions-bar/create-breakout-room/styles.scss

...utton-html5/imports/ui/components/actions-bar/styles.scss

...on-html5/imports/ui/components/activity-check/styles.scss

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

...l5/imports/ui/components/audio/audio-controls/styles.scss

...-html5/imports/ui/components/audio/audio-dial/styles.scss

...html5/imports/ui/components/audio/audio-modal/styles.scss

...l5/imports/ui/components/audio/audio-settings/styles.scss

...-html5/imports/ui/components/audio/audio-test/styles.scss

...on-html5/imports/ui/components/audio/autoplay/styles.scss

...n-html5/imports/ui/components/audio/echo-test/styles.scss

...button-html5/imports/ui/components/audio/help/styles.scss

...ports/ui/components/audio/permissions-overlay/styles.scss

...button-html5/imports/ui/components/banner-bar/styles.scss

...orts/ui/components/breakout-join-confirmation/styles.scss

...ton-html5/imports/ui/components/breakout-room/styles.scss

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

...tton-html5/imports/ui/components/captions/pad/styles.scss

...l5/imports/ui/components/captions/writer-menu/styles.scss