Find .merge-request instead of sleep in MR search spec.

features/steps/project/merge_requests.rb

@@ -501,7 +501,9 @@ class Spinach::Features::ProjectMergeRequests < Spinach::FeatureSteps
 
   step 'I fill in merge request search with "Fe"' do
     fill_in 'issuable_search', with: "Fe"
-    sleep 3
+    page.within '.merge-requests-holder' do
+      find('.merge-request')
+    end
   end
 
   step 'I click the "Target branch" dropdown' do