Realtime editing auto-save hangs when the save request fails at network level

Follow these steps to reproduce:

• edit a page in WYSIWYG edit mode (in-place or standalone)
• perform a save (Alt+Shift+S)
• locate the save request in the Network tab and block it
• make some change and wait for autosave to be triggered

Expected: the autosave is triggered, the save fails, the toolbar status remains "Unsaved", the Done button is re-enabled, auto-save is retried after some time

Actual: the toolbar status remains "Saving", the Done button remains disabled, auto-save is not retried.