docs(storybook): update component docs for dropDownMenu/sidePanel (EN…

…G-56423)

src/components/DropdownMenu.js

@@ -161,7 +161,8 @@ DropdownMenu.propTypes = {
     /** Whether to show error message. */
     showErrorMessage: PropTypes.bool,
     // eslint-disable-next-line max-len
-    /** Whether request called with a custom URL or use the default URL from Gateway at '/-/v3/dropdown_menu/data'*/
+    /** The URL to fetch data for populating the drop-down menu.
+     * If not provided, a default URL will be used to fetch data from Gateway.*/
     requestUrl: PropTypes.string,
     /** The menu items. */
     customValues: PropTypes.arrayOf(

src/components/SidePanel.js

@@ -135,9 +135,10 @@ SidePanel.propTypes = {
     size: PropTypes.oneOf(['small', 'large']),
     /** The margin top */
     top: PropTypes.number,
-    /** The margin top */
+    /** Specifies the stack order of the component,
+     * higher values are rendered in front of lower values. */
     zIndex: PropTypes.number,
-    /** A callback that will be called when a user clicks mask, close button */
+    /** Function invoked when the close button is clicked. */
     onClose: PropTypes.func.isRequired,
     /** Child components */
     children: PropTypes.oneOfType([