long messages get converted to html type and this is problematic

the "show more" for long messages is a well known annoyance, it is implemented as a hack using the HTML mail message type, and this is bad, there is no way to know if message was a long message or actually an HTML message, the problem with editing is also there (see https://github.com/chatmail/core/issues/6561)

I think it is better to remove that behavior from core and instead do the truncation+show-more in the UI

that will allow editing long messages and solve the copying text problem

I have received several reports from people complaining they can't edit long messages

another related problem I noticed with incoming messages: a short message can be edited and then become pretty long, then core will not do the "show more" behavior and instead will at some point truncate the message with `[...]` without possibility to see the full message, this is affecting the "voice to text" bot that starts transcribing voice messages and sends the transcription progressively updating/editing the message instead of having to wait for the full transcription to finish to send then the full message