curses: Fix calculation of columns for CJK text.
* pinentry/pinentry-curses.c (STRWIDTH): New. (collect_line): Let return value for columns width. LEN minus one. (dialog_create): Calculate for the columns with STRWIDTH.
- GnuPG-bug-id: T4598
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>