Global Search - Project Filter sets Group

What does this MR do?

Not sure when this happened, but I noticed this today in PROD today that project.namespace_id is no longer being returned from the /projects RESTful API 🤔 It is returning project.namespace.id however. A quick change can be administered to fix this but I am not sure how/why this happened.

Screenshots (strongly suggested)

	Regression	Fix
Setting Project Filter

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

Related to #299213 (closed)