IPv6 validation not implemented in Assert-ScopeParameter function

[coderabbitai]

Problem

The Assert-ScopeParameter function in source/Modules/DhcpServerDsc.Common/Public/Assert-ScopeParameter.ps1 currently accepts both 'IPv4' and 'IPv6' in its AddressFamily parameter ValidateSet, but the implementation only supports IPv4 validation.

The function logic uses IPv4-specific assumptions:

• Loops through 4 bytes (0..3) for address validation
• Uses IPv4-style subnet mask format and validation
• Would fail or produce incorrect results when IPv6 parameters are provided

Options to resolve

Option A (immediate): Restrict ValidateSet to only 'IPv4' to match current implementation
Option B (future): Implement full IPv6 support with 16-byte address handling, prefix length notation, and appropriate validation logic

References

• PR: Convert nested modules to buildable modules #96
• Comment: Convert nested modules to buildable modules #96 (comment)
• Requested by: @dan-hughes