fix(upgrade): detect downgrades at minor and patch levels

version_lt kept the whole version as a single array element, so the
arithmetic comparison failed and the function always returned false.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/openldap-upgrade/assets/scripts/common.sh

@@ -14,7 +14,9 @@ extract_version() {
 
 version_lt() {
     local IFS=.
-    local -a v1=("$1") v2=("$2")
+    local -a v1 v2
+    read -ra v1 <<< "$1"
+    read -ra v2 <<< "$2"
     for i in 0 1 2; do
         local a=${v1[i]:-0} b=${v2[i]:-0}
         (( 10#$a < 10#$b )) && return 0