Replace fa-spinner in metrics dashboard

yaml loading view

app/views/projects/blob/viewers/_metrics_dashboard_yml_loading.html.haml

-= icon('spinner spin fw')
+= loading_icon(css_class: "gl-vertical-align-text-bottom mr-1")
 = _('Metrics Dashboard YAML definition') + '…'
 
 = link_to _('Learn more'), help_page_path('operations/metrics/dashboards/yaml.md')

changelogs/unreleased/mw-replace-spinner-in-metrics-dashboard-yml-loading.yml

+---
+title: Replace fa-spinner in metrics dashboard yaml definition
+merge_request: 48227
+author:
+type: changed