Limit snippet blob height to 500px

Changelog: changed

MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/75942
Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/255175

app/assets/stylesheets/framework/snippets.scss

@@ -16,6 +16,11 @@
 .snippet-file-content {
   border-radius: 3px;
 
+  .file-content {
+    max-height: 500px;
+    overflow-y: auto;
+  }
+
   + .snippet-file-content {
     @include gl-mt-5;
   }