test(stryker): enable StrykerJS in `elements` package

[nicojs]

StrykerJS 8.0 supports vitest's browser mode 🎉

This PR re-enables StrykerJS on the elements package.

[nicojs]

Mutation testing isn't working as expected yet. See https://github.com/stryker-mutator/stryker-js/issues/4634

[nx-cloud[bot]]

☁️ Nx Cloud Report

CI is running/has finished running commands for commit 9b1a7c5fe90f76cea5c58b5b04ca487556b32eca. As they complete they will appear below. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this CI Pipeline Execution

---

✅ Successfully ran 1 target

• nx affected --target=lint:prettier,lint,build,test

---

Sent with 💌 from NxCloud.

[bundlemon[bot]]

BundleMon (elements)

Unchanged files (3)

Status	Path	Size	Limits
:white_check_mark:	index.js	268.71KB	-
:white_check_mark:	mutation-test-elements.js	198.38KB	-
:white_check_mark:	index.cjs	198.38KB	-

No change in files bundle size

Final result: :white_check_mark:

View report in BundleMon website ➡️

---

Current branch size history | Target branch size history