Resolve "Detail view of Sentry error in GitLab"

What does this MR do?

This adds two endpoints for frontend to consume:

• GET /<project>/error_tracking/<error_id>/details => Provides extended errr=or details
• GET /<project>/error_tracking/<error_id>/stack_trace => Provides the latest stack trace from the error

Both endpoints are cached using reactive_caching.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Related to #32464 (closed)