Minor fixes for LDAP and RDP

[NeffIsBack]

Description

Small fixes for issues I encountered in LDAP and RDP:

• If there is a container with the same name as a group previously the LDAP query crashed because it got the container instead of the group -> Filtering for groups only
• If security principals are part of a group the query crashes when displaying that entity because they are missing a sAMAccountName -> fallback to common name if sAMAccountName is not present
• Eliminate stack traces and protocol crashes when adding the host to the nxcdb fails in RDP

Type of change

Insert an "x" inside the brackets for relevant items (do not delete options)

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Deprecation of feature or functionality
• This change requires a documentation update
• This requires a third party update (such as Impacket, Dploot, lsassy, etc)
• This PR was created with the assistance of AI (list what type of assistance, tool(s)/model(s) in the description)

Setup guide for the review

Run:

• nxc ldap ... --groups users
• nxc rdp <ip-range> a few times until the db fails

Screenshots (if appropriate):

Before&After of the ldap crash(es):

Checklist: