[DS-794] Fix styles of the Virtual Y content page for LB for the Carnation theme

[aleevas]

DS-794

Steps to test:

• [ ] Set Carnation as default theme
• [ ] Enable Layout Builder module.
• [ ] Enable openy_gc_auth_example module.
• [ ] Create Content Type for Layout Builder.
• [ ] Create node and add Virtual Y Content Block via Layout Builder.
• [ ] Create another node with Virtual Y Login Block via Layout Builder.
• [ ] Set up Virtual Y Landing Page url and Virtual Y Login Landing Page url fields on settings page: admin/openy/virtual-ymca
• [ ] Go to Virtual Y Content Block page
• [ ] Verify that Virtual Y menu s sticky and looks good for all type of screen

Desktop:

Tablet:

Mobile:

Quality checks:

Please check these boxes to confirm this PR covers the following cases:

• Maintaining our upgrade path is essential. Check one or the other:
  • [ ] This PR provides updates via hook_update_N or other means.
  • [ ] No updates are necessary for this change.
• Front end fixes should be tested against all of the Open Y Themes.
  • [ ] Tested against Carnation
  • [ ] Tested against Lily
  • [ ] Tested against Rose
  • [ ] This change does not contain front-end fixes.
• [ ] I have flagged this PR "Needs Review" or pinged the VY devs/QA team in Slack