Offer to delete message when trying to save an edit clearing that message

[ShadowJonathan]

In other words, whenever you edit a message, but then immediately clear all the text and try to "save" it, it should pop up "remove this message?"

This behaviour is then consistent with other platforms; (at least)

• Discord
• Telegram

There is a muscle memory of Up Arrow -> ctrl+A -> Backspace -> Enter to delete the latest message.

As of right now (Element Web 1.7.30) this does nothing when trying to save a message when the prompt is cleared, neither when pressing enter or clicking the "save" button manually.

[t3chguy]

Duplicate of #11024

[ShadowJonathan]

Oh, tried to search for it beforehand, thanks!