Fixed merge request locked icon size

Closes #40876

app/views/projects/_md_preview.html.haml

@@ -2,7 +2,7 @@
 
 - if defined?(@merge_request) && @merge_request.discussion_locked?
   .issuable-note-warning
-    = icon('lock', class: 'icon')
+    = sprite_icon('lock', size: 16, css_class: 'icon')
     %span
       = _('This merge request is locked.')
       = _('Only project members can comment.')

app/views/shared/notes/_notes_with_form.html.haml

@@ -27,7 +27,7 @@
 - elsif discussion_locked
   .disabled-comment.text-center.prepend-top-default
     %span.issuable-note-warning
-      %span.icon= sprite_icon('lock', size: 14)
+      = sprite_icon('lock', size: 16, css_class: 'icon')
       %span
         This
         = issuable.class.to_s.titleize.downcase

changelogs/unreleased/merge-request-lock-icon-size-fix.yml

+---
+title: Fixed merge request lock icon size
+merge_request:
+author:
+type: fixed