Fix create_edit_delete_epic_spec.rb test flakiness

qa/qa/ee/page/group/epic/show.rb

@@ -28,7 +28,7 @@ module QA
             def add_issue_to_epic(issue_url)
               click_element :add_issues_button
               fill_element :add_issue_input, issue_url
-              click_element :add_issue_button
+              click_body
               click_element :add_issue_button
             end
 

qa/qa/page/base.rb

@@ -156,6 +156,10 @@ module QA
         click_link text
       end
 
+      def click_body
+        find('body').click
+      end
+
       def self.path
         raise NotImplementedError
       end