Fixed issue with move dropdown not being searchable

Closes #18634

app/assets/javascripts/issuable_form.js.coffee

@@ -102,6 +102,10 @@ class @IssuableForm
             return {
               results: data
             }
+          data: (query) ->
+            {
+              search: query
+            }
         formatResult: (project) ->
           project.name_with_namespace
         formatSelection: (project) ->

app/controllers/autocomplete_controller.rb

@@ -35,6 +35,7 @@ class AutocompleteController < ApplicationController
     project = Project.find_by_id(params[:project_id])
 
     projects = current_user.authorized_projects
+    projects = projects.search(params[:search]) if params[:search].present?
     projects = projects.select do |project|
       current_user.can?(:admin_issue, project)
     end