Apply GitLab UI button styles to buttons in app/views/shared directory

Instructions

For instructions about how to apply GitLab UI button styles to the button instances on these templates, see the epic &4001 (closed).

Files in directory with buttons that needs migration

• app/views/shared/_auto_devops_callout.html.haml
• app/views/shared/_broadcast_message.html.haml
• app/views/shared/_clone_panel.html.haml
• app/views/shared/_confirm_fork_modal.html.haml
• app/views/shared/_delete_label_modal.html.haml
• app/views/shared/_file_picker_button.html.haml
• app/views/shared/_flash_user_callout.html.haml
• app/views/shared/_label.html.haml
• app/views/shared/_mobile_clone_panel.html.haml
• app/views/shared/_new_project_item_select.html.haml
• app/views/shared/_no_ssh.html.haml
• app/views/shared/_remote_mirror_update_button.html.haml