[Interactive Graph Storybook] Give Storybook preview a fixed width (#…

…1545)

## Summary:
Something caused the storybook preview to collapse horizontally.

Adding a fixed width here so that the graph can be viewed.

Issue: none

## Test plan:
Storybook
- http://localhost:6006/?path=/docs/perseuseditor-widgets-interactive-graph--docs

## Screenshots:

| Before | After |
| --- | --- |
| ![Screenshot 2024-08-22 at 11 58 29 AM](https://github.com/user-attachments/assets/d483be2d-bced-4a7a-be86-6ea95bc0d32a) | <img width="571" alt="Screenshot 2024-08-22 at 12 01 42 PM" src="https://github.com/user-attachments/assets/8d77a2e3-b6a7-40d0-b43a-010d769d95f1"> |

Author: nishasy

Reviewers: mark-fitzgerald

Required Reviewers:

Approved By: mark-fitzgerald

Checks: ✅ codecov/project, ✅ codecov/patch, ✅ Upload Coverage (ubuntu-latest, 20.x), ✅ gerald, ⏭️  Publish npm snapshot, ✅ Check builds for changes in size (ubuntu-latest, 20.x), ✅ Cypress (ubuntu-latest, 20.x), ✅ Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ✅ Jest Coverage (ubuntu-latest, 20.x), ✅ Check for .changeset entries for all changed files (ubuntu-latest, 20.x), 🚫 Upload Coverage, ✅ gerald, ⏭️  Publish npm snapshot, 🚫 Jest Coverage (ubuntu-latest, 20.x), 🚫 Cypress (ubuntu-latest, 20.x), 🚫 Check builds for changes in size (ubuntu-latest, 20.x), 🚫 Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ✅ Check for .changeset entries for all changed files (ubuntu-latest, 20.x), ✅ Publish Storybook to Chromatic (ubuntu-latest, 20.x), ✅ gerald

Pull Request URL: #1545

packages/perseus-editor/src/__stories__/editor-page-with-storybook-preview.tsx

@@ -137,6 +137,7 @@ const styles = StyleSheet.create({
     panel: {
         position: "fixed",
         right: 0,
+        minWidth: 500,
         height: "90vh",
         overflow: "auto",
         flex: "none",