build(deps-dev): bump @shopify/react-testing from 5.4.0 to 6.0.0

Bumps [@shopify/react-testing](https://github.com/Shopify/quilt/tree/HEAD/packages/react-testing) from 5.4.0 to 6.0.0.
- [Release notes](https://github.com/Shopify/quilt/releases)
- [Changelog](https://github.com/Shopify/quilt/blob/main/packages/react-testing/CHANGELOG.md)
- [Commits](https://github.com/Shopify/quilt/commits/@shopify/[email protected]/packages/react-testing)

---
updated-dependencies:
- dependency-name: "@shopify/react-testing"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

packages/apps/shopify-app-remix/package.json

@@ -82,7 +82,7 @@
     "@remix-run/testing": "^2.11.2",
     "@shopify/generate-docs": "^0.16.4",
     "@shopify/polaris": "^12.18.0",
-    "@shopify/react-testing": "^5.4.0",
+    "@shopify/react-testing": "^6.0.0",
     "@shopify/shopify-app-session-storage-memory": "^4.0.7",
     "@types/jsonwebtoken": "^9.0.7",
     "@types/react": "^18.3.9",