Protected page with USer group shows page doesnt exists error

## Bug description

We have Dev portal hosted on top of Internal API management instance, we wanted to protect all the pages from anonymous access. So, in page settings for all the pages, under testing its kept to be accessible by developer's user group.

Now when I load the home page it says, "Page you are looking for doesn't exists".

## Reproduction steps

1. Go to pages in admin
2. click on settings and make home page accessible only to certain group
3. Publish the portal
4. Try to navigate to home page in normal mode

## Expected behavior

Page should be throwing User not authorized to view this page

## Is self-hosted portal?
Yes

> [!WARNING]
> "Managed developer portal issues" will be closed automatically. See above for more details.

## Release tag or commit SHA (if using self-hosted version)

[e.g., release `2.0.0`, commit `c45da9778b70d369aba60fa2e63c191efe2b548f`]

## API Management service name

[azusam1lwv787](https://portal.azure.com/#@sodexo.onmicrosoft.com/resource/subscriptions/6e3fc63f-851b-4fc7-8499-48f6a9c28a65/resourceGroups/ist-glb-use2-sas-uat-rg01/providers/Microsoft.ApiManagement/service/azusam1lwv787)

## Environment

UAT

Reproduce the self-hosted portal flow by restricting the home page to the developers' user group, publishing it, and opening it anonymously. Compare the resulting “page doesn't exist” response with the expected unauthorized message, then locate the page-access and error-handling entry points. Done means unauthorized users receive the intended authorization error while permitted users can still open the page.

Written by the indexing model from the issue text.