Use the project full path with namespace in PA

What does this MR do?

Use the project full path with namespace in PA

In productivity analytics the backend expects the full path to the project namespace to find the DB record. This change ensures that the full path to the project is sent via the frontend.

This is behind the productivity_analytics feature flag.

Partially resolves #32048 (closed)

Screenshots

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