Increases pipeline graph drowdown width in order to prevent strange position on chrome on ubuntu

What does this MR do?

Increases the min-width of the mini pipeline graph dropdown in order to prevent the dropdown list items to break on chrome on ubuntu.

Screenshots (if relevant)

Before

After

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • 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 #26218 (closed)