Fix dropdown from the project welcome page moving out of the screen

What does this MR do?

Fixes the dropdown positioning for the welcome page of a project on really small screens (height wise)

Screenshots (if relevant)

Desktop

Mobile

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them

What are the relevant issue numbers?

closes #47966 (closed)