Bump @wordpress/e2e-test-utils from 10.12.0 to 10.21.0

Bumps [@wordpress/e2e-test-utils](https://github.com/WordPress/gutenberg/tree/HEAD/packages/e2e-test-utils) from 10.12.0 to 10.21.0.
- [Release notes](https://github.com/WordPress/gutenberg/releases)
- [Changelog](https://github.com/WordPress/gutenberg/blob/trunk/packages/e2e-test-utils/CHANGELOG.md)
- [Commits](https://github.com/WordPress/gutenberg/commits/@wordpress/e2e-test-utils@10.21.0/packages/e2e-test-utils)

---
updated-dependencies:
- dependency-name: "@wordpress/e2e-test-utils"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -176,7 +176,7 @@
 		"@wordpress/data-controls": "2.2.7",
 		"@wordpress/dependency-extraction-webpack-plugin": "4.28.0",
 		"@wordpress/dom": "3.27.0",
-		"@wordpress/e2e-test-utils": "10.12.0",
+		"@wordpress/e2e-test-utils": "10.21.0",
 		"@wordpress/e2e-test-utils-playwright": "wp-6.4",
 		"@wordpress/e2e-tests": "^4.6.0",
 		"@wordpress/element": "5.22.0",