Improve command palette metrics tracking 5

What does this MR do and why?

User clicks a merge request result in the command palette

This is a part of large set of internal events we are adding to command palette and global search.

Here is a spreadsheet of all events and requested data to be collected Google Sheet.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

1. Make sure advanced search is installed and enabled
2. Make sure you enable zoekt.
3. In terminal run

   rails runner scripts/internal_events/monitor.rb click_merge_request_result_in_command_palette

4. On any gitlab page press '/'
5. Search for any merge_request, click result
6. Watch the terminal to indicate the hit

Related to #438845