g10: Fix garbled status messages in NOTATION_DATA

* g10/cpr.c (write_status_text_and_buffer): Fix off-by-one

Depending on the escaping and line wrapping the computed remaining
buffer length could be wrong. Fixed by always using a break to
terminate the escape detection loop. Might have happened for all
status lines which may wrap.

• GnuPG-bug-id: T6027