Quick Start tour feedback based updates and fixes. Part 1

Created by: erzhtor

• Make the checkbox icon-color when at 0 completed and make the distance between the icon and text 4px. Figma
• Move inside Quick start when displayed vertically. Figma
• Fix styles for file container bottom gap caused by "quick start" tour
• Fix styles for language selector in dark mode/theme
• Disable SignUp/IDE/BEXT install CTA on results/file pages when showing tour info panel
• Remove "Quickly Understand a new codebase", the word isn’t worth the line break and alignment issues.

See slack thread

Moved rest of the changes/updates to a separate issue #33650 (closed)