Fix icon size for usage quotas and billing

Changelog: fixed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/65650
EE: true

ee/app/views/layouts/nav/sidebar/_profile_billing_link.html.haml

@@ -2,7 +2,7 @@
   = nav_link(controller: :billings) do
     = link_to profile_billings_path do
       .nav-icon-container
-        = custom_icon('credit_card')
+        = sprite_icon('credit-card')
       %span.nav-item-name
         = _("Billing")
     %ul.sidebar-sub-level-items.is-fly-out-only

ee/app/views/layouts/nav/sidebar/_profile_usage_quotas_link.html.haml

 = nav_link(controller: :usage_quotas) do
   = link_to profile_usage_quotas_path do
     .nav-icon-container
-      = custom_icon('pipeline')
+      = sprite_icon('pipeline')
     %span.nav-item-name
       = s_('UsageQuota|Usage Quotas')
   %ul.sidebar-sub-level-items.is-fly-out-only