Dropdown story with answerless data (#2305)

## Summary:
Create a Storybook story for the Dropdown widget that renders with answerless data, is interactive, and is scorable.

Issue: LEMS-2930

## Test plan:
- Confirm all checks pass
- Confirm story renders, is interactive, and can be scored

Author: Myranae

Reviewers: jeremywiebe, benchristel, Myranae, handeyeco

Required Reviewers:

Approved By: jeremywiebe, benchristel

Checks: ✅ 8 checks were successful

Pull Request URL: #2305

Author: Myranae

.changeset/quiet-insects-agree.md

@@ -0,0 +1,5 @@
+---
+"@khanacademy/perseus": minor
+---
+
+Add a story for Dropdown that uses answerless data

packages/perseus-core/src/utils/split-perseus-item.ts

@@ -5,6 +5,10 @@ import {getUpgradedWidgetOptions} from "../widgets/upgrade";
 
 import type {PerseusRenderer} from "../data-schema";
 
+/**
+ * Upgrades widget options and removes answerful data for all the widgets in a
+ * Perseus item.
+ */
 export default function splitPerseusItem(
     originalItem: PerseusRenderer,
 ): PerseusRenderer {

packages/perseus/src/widgets/dropdown/dropdown.stories.tsx

@@ -1,3 +1,4 @@
+import {splitPerseusItem} from "@khanacademy/perseus-core";
 import * as React from "react";
 
 import {RendererWithDebugUI} from "../../../../../testing/renderer-with-debug-ui";
@@ -41,3 +42,7 @@ export const DropdownWithEmptyPlaceholder = (
 ): React.ReactElement => {
     return <RendererWithDebugUI question={dropdownWithEmptyPlaceholder} />;
 };
+
+export const DropdownWithNoAnswers = (args: StoryArgs): React.ReactElement => {
+    return <RendererWithDebugUI question={splitPerseusItem(basicDropdown)} />;
+};