[gbsyncd]: Set SYSLOG_CONFIG_FEATURE for gbsyncd (#17325)

Why I did it
SONiC Mgmt test syslog/test_syslog_rate_limit.py syslog.test_syslog_rate_limit test_syslog_rate_limit was failing on SKUs with gbsyncd. This includes Arista 720DT when testing on the 202305 branch.

How I did it
The issue was no value for gbsyncd in "show syslog rate-limit-container",
because gbsyncd is not having a SYSLOG_CONFIG_FEAGTURE|gbsyncd entry in
config_db, which is further because gbsyncd feature is for not enabled
through init_cfg.json.j2.

How to verify it
Test is now passing on 720DT in 202305 branch.

Co-authored-by: Boyang Yu <byu@arista.com>

files/scripts/gbsyncd.sh

@@ -10,6 +10,7 @@ function startplatform() {
         if [ -z $($DB_CLI CONFIG_DB HGET 'FEATURE|gbsyncd' state) ]; then
             local CMD="local r=redis.call('DUMP', KEYS[1]); redis.call('RESTORE', KEYS[2], 0, r)"
             $DB_CLI CONFIG_DB EVAL "$CMD" 2 'FEATURE|syncd' 'FEATURE|gbsyncd'
+            $DB_CLI CONFIG_DB EVAL "$CMD" 2 'SYSLOG_CONFIG_FEATURE|syncd' 'SYSLOG_CONFIG_FEATURE|gbsyncd'
         fi
     done
 }