Add material design icons to admin/settings views (#27780)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/views/admin/export_domain_blocks/_domain_block.html.haml

@@ -23,5 +23,5 @@
         = f.object.public_comment
       - if existing_relationships
         ·
-        = fa_icon 'warning fw'
+        = material_symbol 'warning'
         = t('admin.export_domain_blocks.import.existing_relationships_warning')

app/views/admin/export_domain_blocks/import.html.haml

@@ -12,7 +12,7 @@
       %label.batch-table__toolbar__select.batch-checkbox-all
         = check_box_tag :batch_checkbox_all, nil, false
       .batch-table__toolbar__actions
-        = f.button safe_join([fa_icon('copy'), t('admin.domain_blocks.import')]),
+        = f.button safe_join([material_symbol('content_copy'), t('admin.domain_blocks.import')]),
                    class: 'table-action-link',
                    data: { confirm: t('admin.reports.are_you_sure') },
                    name: :save,