fix(dropdown): fix zindex of DropdownButton (#283)

Author: ehsan-github

src/components/dropdown-button/styles.ts

@@ -2,13 +2,13 @@ export default {
   container: {
     position: 'relative',
     cursor: 'pointer',
-    zIndex: 5,
     marginTop: '-2px',
     width: 'fit-content',
   },
   dropdown: (height: number | undefined, alignLeft: boolean) => ({
     position: 'absolute',
     top: `${height}px`,
+    zIndex: 5,
     ...(alignLeft
       ? {
           right: '0px',