Stop updating pages configuration on disk if feature flag is disabled

What does this MR do?

In &4851 (closed) we want stop touching pages NFS share.

This MR stops updating pages config files if corresponding feature is disabled.

Not that it's hard to scope feature flag by project, because projects can be renamed/moved, and we only update some of them, then we may end up with an inconsistent state on disk.

See the previous MRs:

• !50683 (merged)
• !53363 (merged)

Screenshots (strongly suggested)

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 #300619 (closed)