Remove .new-issue-link

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

app/assets/stylesheets/framework/mobile.scss

@@ -66,8 +66,7 @@
 
 @include media-breakpoint-down(sm) {
   .page-title {
-    .note-created-ago,
-    .new-issue-link {
+    .note-created-ago {
       display: none;
     }
   }

app/views/projects/issues/show.html.haml

@@ -55,7 +55,7 @@
     - if can_report_spam
       = link_to 'Submit as spam', mark_as_spam_project_issue_path(@project, @issue), method: :post, class: 'd-none d-sm-none d-md-block btn btn-grouped btn-spam', title: 'Submit as spam'
     - if can_create_issue
-      = link_to new_project_issue_path(@project), class: 'd-none d-sm-none d-md-block btn btn-grouped new-issue-link btn-success btn-inverted', title: 'New issue', id: 'new_issue_link' do
+      = link_to new_project_issue_path(@project), class: 'd-none d-sm-none d-md-block btn btn-grouped btn-success btn-inverted', title: 'New issue', id: 'new_issue_link' do
         New issue
 
 .issue-details.issuable-details