Update aria-labels on landmarks

[bethcollins92]

Done

• Removed the word "navigation" from all aria-label's on <nav> elements, to fix duplication with screen readers.
• Checked all <header> and <main> tags too

Fixes #4133

QA

• Open demo
• Use VoiceOver on the navigation landmarks such as pagination or side navigation to check duplication has been removed
• Check out this PR, in VsCode search for navigation" and there should be no more instances of the word navigation in nav elements

Check if PR is ready for release

If this PR contains Vanilla SCSS code changes, it should contain the following changes to make sure it's ready for the release:

• PR should have one of the following labels to automatically categorise it in release notes:
  • Feature 🎁, Breaking Change 💣, Bug 🐛, Documentation 📝, Maintenance 🔨.
• Vanilla version in package.json should be updated relative to the most recent release, following semver convention:
  • if CSS class names are not changed it can be bugfix relesase (x.x.X)
  • if CSS class names are changed/added/removed it should be minor version (x.X.0)
  • see the wiki for more details
• Any changes to component class names (new patterns, variants, removed or added features) should be listed on the what's new page.
• Documentation side navigation should be updated with the relevant labels.

[webteam-app]

Demo starting at https://vanilla-framework-4361.demos.haus

[bethcollins92]

@bartaz This PR got lost in the abyss! It wasn't in the review column wupsy. Anyway it looks like a lot of file changes but it's just updating aria-labels etc to avoid duplication on AT. Just tagging you incase you have time to review it on Monday when I'm not here

[bartaz]

LGTM, thanks!