fix: Ensure menus are always kept on the screen (#1036)

* ensuring dropdowns fit on the screen

* refactoring

* fix flow types

* no longer fixing the elements which should resolve scrolling issues

* fix menus that should be fixed

* styled-components syntax was wrong

* account for fixed dropdowns when handling overflowing menus

* Update app/components/DropdownMenu/DropdownMenu.js

Co-Authored-By: Tom Moor <tom.moor@gmail.com>

app/components/Sidebar/components/CollectionLink.js

@@ -62,7 +62,7 @@ class CollectionLink extends React.Component<Props> {
           exact={false}
           menu={
             <CollectionMenu
-              position="left"
+              position="right"
               collection={collection}
               onOpen={() => (this.menuOpen = true)}
               onClose={() => (this.menuOpen = false)}