Update existing test due to page object renaming

qa/qa/specs/features/ee/browser_ui/2_plan/issues_weight/issue_weight_visualization_spec.rb

@@ -41,8 +41,8 @@ module QA
           show.click_milestone_link
         end
 
-        Page::Project::Milestone::Index.perform do |index|
-          expect(index.total_issue_weight_value).to have_content(weight)
+        Page::Project::Milestone::Show.perform do |show|
+          expect(show.total_issue_weight_value).to have_content(weight)
         end
 
         Page::Project::Menu.perform(&:click_issues)