cache node_modules in ci tests

[Hamms]

Links

• Jira:

Testing story

Deployment strategy

Follow-up work

Privacy

Security

Caching

PR Checklist:

• [ ] Tests provide adequate coverage
• [ ] Privacy and Security impacts have been assessed
• [ ] Code is well-commented
• [ ] New features are translatable or updates will not break translations
• [ ] Relevant documentation has been added or updated
• [ ] User impact is well-understood and desirable
• [ ] Pull Request is labeled appropriately
• [ ] Follow-up work items (including potential tech debt) are tracked and linked