fix(Dropdown): add checking if ref exists on dropdown (#958)

* fix: add checking if ref exists on dropdown

* Update src/Dropdown.tsx

Co-authored-by: Jason Quense <monastic.panic@gmail.com>

* linting

Co-authored-by: Jason Quense <monastic.panic@gmail.com>

src/Dropdown.tsx

@@ -278,7 +278,7 @@ function Dropdown({
           (e) => {
             if (
               (e.key === 'Tab' && !e.target) ||
-              !menuRef.current!.contains(e.target as HTMLElement)
+              !menuRef.current?.contains(e.target as HTMLElement)
             ) {
               onToggle(false, event);
             }