Add btn-default class for edit buttons in admin projects and groups

app/views/admin/groups/_group.html.haml

@@ -33,5 +33,5 @@
       = visibility_level_icon(group.visibility_level)
 
   .controls.gl-flex-shrink-0.gl-ml-5
-    = link_to _('Edit'), admin_group_edit_path(group), id: "edit_#{dom_id(group)}", class: 'gl-button btn'
+    = link_to _('Edit'), admin_group_edit_path(group), id: "edit_#{dom_id(group)}", class: 'btn gl-button btn-default'
     = link_to _('Delete'), [:admin, group], data: { confirm: _("Are you sure you want to remove %{group_name}?") % { group_name: group.name } }, method: :delete, class: 'gl-button btn btn-danger'

app/views/admin/projects/_projects.html.haml

@@ -4,7 +4,7 @@
       - @projects.each_with_index do |project|
         %li.project-row{ class: ('no-description' if project.description.blank?) }
           .controls
-            = link_to 'Edit', edit_project_path(project), id: "edit_#{dom_id(project)}", class: "gl-button btn"
+            = link_to 'Edit', edit_project_path(project), id: "edit_#{dom_id(project)}", class: "btn gl-button btn-default"
             %button.delete-project-button.gl-button.btn.btn-danger{ data: { delete_project_url: admin_project_path(project), project_name: project.name } }
               = s_('AdminProjects|Delete')