Non-ASCII chars in System's configured FTN origin lines could cause problem for exported echomail "charset/CHRS" values

In this scenario (which has never been observed/reported):

1. If the message body doesn't contain any non-ASCII chars, SBBSecho will give it the "ASCII 1" charset/CHRS value, which would be incorrect.
2. If the message body contains any UTF-8 chars, the message would be flagged as UTF-8 and thus the origin line would contain invalid UTF-8 sequences.