Fix dropdown position for the new button on mobile for the top navbar

What does this MR do?

Fixes the dropdown position for mobile screens on the top navbar for the new button

Screenshots (if relevant)

Before

After

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

closes #34139 (closed)