[utilities][ulog] fix ulog backend color log length calculation error
[utilities][ulog] fix ulog backend color log length calculation error

Signed-off-by: chenyong <c5088770d2c661f197bfb271fa63d3fc8c74d84f@rt-thread.com>

hezlog/rt-thread,armink/rt-thread,ArdaFu/rt-thread,weety/rt-thread,hezlog/rt-thread,weety/rt-thread,hezlog/rt-thread,weety/rt-thread,nongxiaoming/rt-thread,ArdaFu/rt-thread,nongxiaoming/rt-thread,geniusgogo/rt-thread,hezlog/rt-thread,hezlog/rt-thread,nongxiaoming/rt-thread,ArdaFu/rt-thread,RT-Thread/rt-thread,armink/rt-thread,weety/rt-thread,RT-Thread/rt-thread,armink/rt-thread,RT-Thread/rt-thread,RT-Thread/rt-thread,geniusgogo/rt-thread,weety/rt-thread,nongxiaoming/rt-thread,geniusgogo/rt-thread,ArdaFu/rt-thread,ArdaFu/rt-thread,RT-Thread/rt-thread,hezlog/rt-thread,geniusgogo/rt-thread,nongxiaoming/rt-thread,weety/rt-thread,armink/rt-thread,armink/rt-thread,geniusgogo/rt-thread,weety/rt-thread,nongxiaoming/rt-thread,RT-Thread/rt-thread,ArdaFu/rt-thread,RT-Thread/rt-thread,armink/rt-thread,hezlog/rt-thread,geniusgogo/rt-thread,ArdaFu/rt-thread,nongxiaoming/rt-thread,armink/rt-thread,geniusgogo/rt-thread