Suggestions sort order is alphabetical, but should be based on ML score

Suggestions sort order is alphabetical but should be based on ML score

How to reproduce this bug

1. Navigate to this particular MR
2. Observe the suggested reviewers on the dropdown field on the side-bar are ordered by name alphabetically
3. Running the internal client via Rails console confirm that the names were re-ordered

   [ gprd ] production> c = ::Gitlab::AppliedMl::SuggestedReviewers::Client.new
   => #<Gitlab::AppliedMl::SuggestedReviewers::Client:0x00007f73ec8063a0 @rpc_url="api.unreview.io:443", @certs="snipped">
   
   [ gprd ] production> c.suggested_reviewers(merge_request_iid: 57, project_id: 32318686, changes: ['db/db.go', 'proto/ruby/bot/recommender_pb.rb'], author_username: 'a_akgun')
   => {:version=>"0.0.0", :top_n=>5, :reviewers=>["tle_gitlab", "AndrasHerczeg", "achueshev", "srayner"]}