fix: remove unused namespace

src/main/frontend/components/content.cljs

@@ -14,7 +14,6 @@
             [frontend.handler.image :as image-handler]
             [frontend.handler.notification :as notification]
             [frontend.handler.page :as page-handler]
-            [frontend.handler.whiteboard :as whiteboard-handler]
             [frontend.mixins :as mixins]
             [frontend.state :as state]
             [frontend.ui :as ui]