This change might be controversal.
According to the `test_forward_quote` test
(introduced in 6b3b33d2a0,
https://github.com/chatmail/core/pull/2843),
this behavior is intentional.
That MR only removed the message ID assignment
but did _not_ remove the text altogether.
On the other hand other messengers, including Telegram and WhatsApp,
don't do this (they don't forward quotes together with messages).
I argue that doing this is not expected by most users,
and is bad for privacy.
Forwarding a message should only forward that message,
and not carry any more information.
How I came to this: I was working on
https://github.com/chatmail/core/issues/8053
trying to undestand why the quoted message ID defaults
to the last message of the target chat.
And, thanks to 3f27be9bcb,
I questioned: "Why are we forwarding quotes in the first place?".
So this also closes https://github.com/chatmail/core/issues/8053.
Note that this commit does not alter `quoted_message()`.
That's for displaying old messages,
and for compatibility with senders that do not remove the quote
from forwarded messages.
e28672f37b