[fix](multi-catalog)the classpath of custom lib should put back of fe…

… jars (apache#35986)

see apache#34990
user class maybe use some tripartite lib, we should put them back of fe
jars to avoid conflicts

bin/start_fe.sh

@@ -204,7 +204,7 @@ done
 # add custome_libs to CLASSPATH
 if [[ -d "${DORIS_HOME}/custom_lib" ]]; then
  for f in "${DORIS_HOME}/custom_lib"/*.jar; do
- CLASSPATH="${f}:${CLASSPATH}"
+ CLASSPATH="${CLASSPATH}:${f}"
  done
 fi