Add My Reaction filter to Vue merge request list app

What does this MR do and why?

For #442920 (closed)

Adds the My-Reaction filter to the Vue-implemented Merge Request list (behind the vue_merge_request_list feature flag).

My-Reaction can be inclusive (=) or exclusive (!=).

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.

Screenshots or screen recordings

Before	After
With the vue_merge_request_list feature flag enabled, there is no option to filter by My-Reaction	Screencast_from_2024-08-22_18-57-27

How to set up and validate locally

1. Enable the vue_merge_request_list feature flag in the rails console rails c => Feature.enable( :vue_merge_request_list )
2. React with different emoji to one or two MRs
3. Navigate to the Merge Request list e.g. http://gdk.test:3000/[YOUR USERNAME]/[THE PROJECT NAMESPACE]/-/merge_requests
4. Begin typing reaction in the search bar and/or select the My-Reaction filter
5. Choose = or !=, plus one of the emoji you reacted with
6. Submit the search / filter
   • Try resubmitting the URL in a new tab to recall the same filters in the UI
   • Try clearing the filter bar and submit the (empty) search to see the URL parameters clear
   • Try the other filter option (= or !=) to see a different set of MRs appear

Bonus validation:

1. BEFORE adding any reactions, try this filter. It will not suggest any emoji to filter by, and only suggest Any/None.
2. Then, add reactions, and try the filter again. It will suggest your personal reactions.