Update views for testability purposes

ee/app/views/projects/issues/export_csv/_button.html.haml

 - if (current_user && @project.feature_available?(:export_issues)) || show_promotions?
   %button.csv_download_link.btn.has-tooltip{ title: _('Export as CSV'),
-    data: { toggle: 'modal', target: '.issues-export-modal' } }
+    data: { toggle: 'modal', target: '.issues-export-modal', qa_selector: 'export_as_csv_button' } }
     = sprite_icon('export')

ee/app/views/projects/issues/export_csv/_modal.html.haml

 - if current_user && @project.feature_available?(:export_issues)
   .issues-export-modal.modal
     .modal-dialog
-      .modal-content
+      .modal-content{ data: { qa_selector: 'export_issues_modal' } }
         .modal-header
           %h3
             = _('Export issues')
@@ -17,6 +17,6 @@
           .modal-text
             = _('The CSV export will be created in the background. Once finished, it will be sent to <strong>%{email}</strong> in an attachment.').html_safe % { email: @current_user.notification_email }
         .modal-footer
-          = link_to _('Export issues'), export_csv_project_issues_path(@project, request.query_parameters), method: :post, class: 'btn btn-success float-left', title: _('Export issues'), data: { track_label: "export_issues_csv", track_event: "click_button", track_value: "" }
+          = link_to _('Export issues'), export_csv_project_issues_path(@project, request.query_parameters), method: :post, class: 'btn btn-success float-left', title: _('Export issues'), data: { track_label: "export_issues_csv", track_event: "click_button", track_value: "", qa_selector: "export_issues_button" }
 - elsif show_promotions?
   = render 'shared/promotions/promote_csv_export'