nsslapd-numlisteners limit is not enforced

[jchapma]

Issue Description
When a invalid value for the attribute nsslapd-numlisteners is used, config normalises the value but the invalid value is written to dse.ldif.

Package Version and Platform:

• Package and version: 389-ds-base-2.3.4-3.el9.x86_64

Steps to Reproduce

1. dsconf localhost config get nsslapd-numlisteners
   nsslapd-numlisteners: 1
2. dsconf localhost config replace nsslapd-numlisteners=5
   Successfully replaced "nsslapd-numlisteners"
3. dsconf localhost config get nsslapd-numlisteners
   nsslapd-numlisteners: 4
4. grep nsslapd-numlisteners /etc/dirsrv/slapd-localhost/dse.ldif
   nsslapd-numlisteners: 5
5. systemctl restart dirsrv@localhost
6. dsconf localhost config get nsslapd-numlisteners
   nsslapd-numlisteners: 4
7. grep nsslapd-numlisteners /etc/dirsrv/slapd-localhost/dse.ldif
   nsslapd-numlisteners: 5

Expected results
Invalid values should return an operations error and not be written to dse.ldif