Make dropdown hint consistent with EE version

What does this MR do?

Make dropdown hint consistent with EE version

EE

const dropdownData = this.tokenKeys.get()

https://gitlab.com/gitlab-org/gitlab-ee/blob/master/app/assets/javascripts/filtered_search/dropdown_hint.js#L59

CE

const dropdownData = gl.FilteredSearchTokenKeys.get()

https://gitlab.com/gitlab-org/gitlab-ce/blob/master/app/assets/javascripts/filtered_search/dropdown_hint.js#L59

Are there points in the code the reviewer needs to double check?

None

Why was this MR needed?

Make CE => EE 🤝🏿

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• 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 #33721 (closed)