Upgrade vanilla and global nav versions

[mtruj013]

Done

• Upgrade Vanilla version to 4.9.1
• Upgrade global nav to 3.6.4

QA

• View the site locally in your web browser at: http://0.0.0.0:8001/
• Check as many pages as possible and see that nothing looks broken

Issue / Card

Fixes #

Screenshots

[If relevant, please include a screenshot.]

Help

QA steps - Commit guidelines

[bartaz]

Demo seems to be up: https://ubuntu-com-13718.demos.haus/

[mtruj013]

Thanks @bartaz, would you mind taking another look?