iservice: rename one_glyph to glyph_size

iservice: rename one_glyph to glyph_size

Throughout the function variables which deal with byte counts have a
_size postfix. one_glyph is the number of bytes in one character.
Reading the code is easier and more consistent this way.

Change-Id: I69a6ab59d995fb4a511f57c8535b5ffa4048673c
Signed-off-by: Heiko Hund <heiko@ist.eigentlich.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1398
Message-Id: <20251124170055.16034-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg34642.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>