Apply GitLab UI styles to shared labels buttons

All buttons (success, default, cancel) within the shared/labels folder have had the gl-button class applied between the  class, and the  class as per guidance in epic &4001

app/views/shared/labels/_form.html.haml

@@ -28,7 +28,7 @@
       = render_suggested_colors
   .form-actions
     - if @label.persisted?
-      = f.submit 'Save changes', class: 'btn btn-success js-save-button'
+      = f.submit 'Save changes', class: 'btn gl-button btn-success js-save-button'
     - else
-      = f.submit 'Create label', class: 'btn btn-success js-save-button qa-label-create-button'
-    = link_to 'Cancel', back_path, class: 'btn btn-cancel'
+      = f.submit 'Create label', class: 'btn gl-button btn-success js-save-button qa-label-create-button'
+    = link_to 'Cancel', back_path, class: 'btn gl-button btn-cancel'

app/views/shared/labels/_nav.html.haml

@@ -15,10 +15,10 @@
       .input-group
         = search_field_tag :search, params[:search], { placeholder: _('Filter'), id: 'label-search', class: 'form-control search-text-input input-short', spellcheck: false, autofocus: true }
         %span.input-group-append
-          %button.btn.btn-default{ type: "submit", "aria-label" => _('Submit search') }
+          %button.btn.gl-button.btn-default{ type: "submit", "aria-label" => _('Submit search') }
             = icon("search")
     = render 'shared/labels/sort_dropdown'
     - if labels_or_filters && can_admin_label && @project
-      = link_to _('New label'), new_project_label_path(@project), class: "btn btn-success qa-label-create-new"
+      = link_to _('New label'), new_project_label_path(@project), class: "btn gl-button btn-success qa-label-create-new"
     - if labels_or_filters && can_admin_label && @group
-      = link_to _('New label'), new_group_label_path(@group), class: "btn btn-success qa-label-create-new"
+      = link_to _('New label'), new_group_label_path(@group), class: "btn gl-button btn-success qa-label-create-new"

changelogs/unreleased/231209-labels-buttons.yml

+---
+title: Apply GitLab UI styles to buttons in app/views/shared/labels directory
+merge_request: 43346
+author: Gary Bell @garybell
+type: other