Describe the bug
When I make a change in my CMS and save it, netlify deploys a preview with https://docs.netlify.com/site-deploys/deploy-previews/. This works flawlessly. However when the preview button shows up, it doesn't link to the preview url, but instead to my default website url.

To Reproduce

1. Go to a "page" collection, in your cms, that deploys a page.
2. Make a change in the content.
3. Click on 'save'
4. Click on 'preview'
5. Check what the url is (does it match the deployed branch?)

Expected behavior
I'd expect to see the preview button link to the new deploy preview url, instead of the base website url.

Is this how it was intended? Or am I missing something in the code? In its current state, the user would have to go to netlify to find the url name.

Applicable Versions:
netlify-cms-app 2.15.60
netlify-cms-core 2.54.1
netlify-cms 2.10.180
provider: github

CMS configuration

site_url: https://my-website.org # hiding for privacy
publish_mode: editorial_workflow
backend:
  name: git-gateway
  branch: master
  squash_merges: true

local_backend: true

media_folder: static/img
public_folder: /img

## Aliases code here
## Removed, since not fully relevant

collections:
    - label: 'Pages'
      name: 'pages'
      label_singular: 'Page'
      folder: 'content/pages'
      create: true
      format: 'json'
      show_preview_links: true
      nested:
        depth: 100 # max depth to show in the collection tree
        summary: '{{meta}}' # optional summary for a tree node, defaults to the inferred title field
      editor:
        preview: false
      fields:
        - << : *TITLE
          label: Page title for within cms
        - *SEO
        - *PAGE-COMPONENTS

Thanks in advance!