<Fixed Layer for viewer-embedded pages> There is no viewer origin header at the top of news page

### Description

There is no viewer origin header at the top of news page

### Reproduction Steps

1. Search for 'nypost news'
2. Click first NYPost AMP link
4. Verify that grey "nypost.com" viewer origin header is at top of page
4. Verify that red "New York Post" header bar is just below origin header
5. Scroll page down
6. Verify that origin header disappeared
6. Verify that header bar is now at top
7. Scroll upward
8. Verify that origin header reappears
9. Verify header bar appears just below origin header

Actual result: There is no grey "nypost.com" viewer origin header at the top of page
http://screencast/cast/NjU2NDI3OTU1MDQ3NjI4OHxiMDdiOTJjMy0xMg

Expected result: Viewer origin header should appear and disappear when user swipes up and down
https://photos.app.goo.gl/24w9Smn9tdHUZLSm6

When page is loaded and user swipes up: https://screenshot.googleplex.com/5mg4qHgT72bM4tE
When user swipes down: https://screenshot.googleplex.com/8fKVm5in7VvP3sC

Note: I can see viewer origin header at the top of page only on Android device on Chrome browser

### Relevant Logs

_No response_

### Browser(s) Affected

Chrome, Firefox, Safari

### OS(s) Affected

_No response_

### Device(s) Affected

_No response_

### AMP Version Affected

_No response_