Make mobile Collections Sidebar hidden on page load (#16878)

...end/src/metabase/collections/components/Header/Header.jsx

...c/metabase/collections/components/Header/Header.styled.js

frontend/src/metabase/collections/constants.js

...src/metabase/collections/containers/CollectionContent.jsx

...ctions/containers/CollectionSidebar/CollectionSidebar.jsx

.../containers/CollectionSidebar/CollectionSidebar.styled.js

...tabase/components/CollectionLanding/CollectionLanding.jsx

.../components/CollectionLanding/CollectionLanding.styled.js

frontend/src/metabase/routes.jsx

...end/src/metabase/styled-components/theme/media-queries.js