Check if we need to reimplement custom behavior for forms in .onion http

!644 (merged) fixed #33298 (closed), but the fix conflicts with the d4e5590f upstream commit that was landed in 116.

We should check if this causes a regression for us or if it's fine.

/cc @jwilde (the author of the upstream patch 😄) and @ma1 (who reviewed the original one downstream)