Fix duplicate detection logic by ensuring exact match on string length (

#6333)

Fix single valued parameters configuration code that accepts multiple comma separated values .
Updated the condition for checking duplicates to ensure that the lengths of the candidate and original strings are equal. This prevents false positives by confirming that the strings are identical at the start and match in length, enforcing an exact duplicate check.

ldap/servers/slapd/charray.c

@@ -354,8 +354,9 @@ slapi_str2charray_ext(char *str, char *brkstr, int allow_dups)
  /* Always copy the first value into the array */
  if ((!allow_dups) && (i != 0)) {
  /* Check for duplicates */
+ size_t len_s = strlen(s);
  for (j = 0; j < i; j++) {
- if (strncmp(res[j], s, strlen(s)) == 0) {
+ if (len_s == strlen(res[j]) && strncmp(res[j], s, len_s) == 0) {
  dup_found = 1;
  break;
  }