[Teams] Adjust styling of Teams menu & pages

[jankeromnes]

Follow-up to #4401

• 1. Team selector font size could be text-sm / 14px: [dashboard] Implement Teams UI (selector, creation wizard, members page, project page) #4401 (comment)
• 2. Team selector dropdown entry title font size could be text-sm / 14px: [dashboard] Implement Teams UI (selector, creation wizard, members page, project page) #4401 (comment)
• 3. Team selector entry could be bg-gray-100 on hover and/or when it's the currently selected team: [dashboard] Implement Teams UI (selector, creation wizard, members page, project page) #4401 (comment)
• 4. When creating a New Team, most of the top menu should be hidden as per the specs: [dashboard] Implement Teams UI (selector, creation wizard, members page, project page) #4401 (comment)
• 5. The URL to create a New Team, currently /new-team, could be improved: [dashboard] Implement Teams UI (selector, creation wizard, members page, project page) #4401 (comment)

[gtsiolis]

Updated the description and resolved items [4] and [5] which have been resolved in #4571. Thanks @jankeromnes! 🏀

[gtsiolis]

Opened follow up #5072 for point [3].

[gtsiolis]

Added #5074 to resolve points [1] and [2].