Disable JIT Kubernetes resource creation for project level clusters

What does this MR do?

Disables functionality added in #57115 (closed) for project level clusters.

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

Performance 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

Test scenarios:

• ci_preparing_state feature flag enabled, group cluster: Project namespace created when deployment job runs

• ci_preparing_state feature flag disabled, group cluster: Project namespace created when project is created

• ci_preparing_state feature flag enabled, project cluster: Project namespace created when cluster is added

• ci_preparing_state feature flag disabled, project cluster: Project namespace created when cluster is added

• Project clusters that provide credentials with insufficient permissions to create project namespace still have credentials passed through to the job.

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

Closes #60500 (closed)