Remove usage of non-conformant font-size 20

This affects 4 files

app/assets/javascripts/releases/components/release_block_header.vue

@@ -42,7 +42,7 @@ export default {
 <template>
   <div class="card-header d-flex align-items-center bg-white pr-0">
-    <h2 class="card-title my-2 mr-auto gl-font-size-20-deprecated-no-really-do-not-use-me">
+    <h2 class="card-title my-2 mr-auto">
       <gl-link v-if="selfLink" :href="selfLink" class="font-size-inherit">
         {{ release.name }}
       </gl-link>

app/assets/stylesheets/framework/common.scss

@@ -557,4 +557,3 @@ img.emoji {
 See https://gitlab.com/gitlab-org/gitlab/issues/36857 for more details.
 **/
 .gl-line-height-14 { line-height: $gl-line-height-14; }
-.gl-font-size-20 { font-size: $gl-font-size-20; }

app/assets/stylesheets/framework/variables.scss

@@ -363,7 +363,6 @@ $gl-header-color: #4c4e54;
 $gl-font-size-12: 12px;
 $gl-font-size-14: 14px;
 $gl-font-size-16: 16px;
-$gl-font-size-20: 20px;
 $gl-font-size-28: 28px;
 $gl-font-size-42: 42px;

app/views/devise/registrations/new.html.haml

@@ -8,7 +8,7 @@
         = _("GitLab is a single application for the entire software development lifecycle. From project planning and source code management to CI/CD, monitoring, and security.")
     .col-lg-5.order-12
       .text-center.mb-3
-        %h2.font-weight-bold.gl-font-size-20-deprecated-no-really-do-not-use-me= _('Register for GitLab')
+        %h2.font-weight-bold= _('Register for GitLab')
       = render 'devise/shared/experimental_separate_sign_up_flow_box'
       = render 'devise/shared/sign_in_link'
 - else

ee/app/assets/javascripts/subscriptions/new/components/order_summary.vue

@@ -49,7 +49,7 @@ export default {
     </div>
     <div class="d-none d-lg-block">
       <div class="append-bottom-20">
-        <h4 class="gl-font-size-20-deprecated-no-really-do-not-use-me">
+        <h4>
           {{ titleWithName }}
         </h4>
       </div>