refactor: un-nest handle_edit_delete

[WofWca]

Back before e10f95b
(#6664) this code was inlined
into add_parts() so it couldn't utilize early returns.
Now it can.

I only decided not to touch the edit_msg_showpadlock part,
because I don't understand the intended meaning of the condition
(this might be a bug).

Related:

• refactor: less nested remove_contact_from_chat #8108

[link2xt]

I only decided not to touch the edit_msg_showpadlock part, because I don't understand the intended meaning of the condition

edit_msg_showpadlock || !original_msg.get_showpadlock() means that if edit message is not encrypted and original message is encrypted, edit should not be applied. So it is not possible to edit "secure" message with "insecure" message.

[WofWca]

Thanks! Makes sense.
I adjusted that part now as well.