This fixes drafts not clearing after posting a reply.
Vue 3.3.11 changed watchers to stop firing after component unmount.
After posting a reply, the post form is removed, now causing the queued
event to be discarded.
Synchronous flush causes the handler to be called immediately when
changes happen, solving the problem.
See: https://github.com/vuejs/core/pull/7181
See: 80e2128d52
Fixes: a7dea2f70fFixes: #413