EnsureAttributes with Provider.AD does not allow to unset attributes

[blindzero]

Description

If attributes are only unset with EnsureAttributes on Provider.AD (maybe others as well?) you'll receive an error about method $null

Steps to Reproduce

1. Create Step with

@{
            Name = 'AD - Remove phone number attributes'
            Type = 'IdLE.Step.EnsureAttributes'
            With = @{
                AuthSessionName = 'AD'
                IdentityKey = '{{Request.IdentityKeys.sAMAccountName}}'
                Provider = 'AD'
                Attributes = @{
                    mobile = $null
                    telephoneNumber = $null
                }
            }
        }

2. Plan + Execute
3. Get Error

Expected Behavior

Attributes are set to $null

Actual Behavior

Error

Cannot bind argument to parameter 'MethodArguments' because it is null.

Environment

• PowerShell version: 7.5.4
• OS: Windows Server 2019
• IdLE version / commit: main branch

Additional Context

Not sure what is breaking it here. It seems that the defined supported / unsupported Attributes of EnsureAttributes is somehow in the way as well. Althought the error message with using

telephoneNumber = '' references to the old EnsureAttribute and not to the new plural one.
Also it refers to "CreateIdentity" not to "EnsureAttributes", what we use here?

Exception calling "EnsureAttribute" with "4" argument(s): "AD Provider: Unsupported attribute in EnsureAttribute operation. 
               Attribute: OtherAttributes

               Supported attributes for EnsureAttribute:
                 - Department
                 - Description
                 - DisplayName
                 - EmailAddress 
                 - GivenName 
                 - Manager
                 - Surname
                 - Title
                 - UserPrincipalName

               Note: Custom LDAP attributes and password attributes are not supported in EnsureAttribute. 
               For custom attributes, use CreateIdentity with OtherAttributes."

We need to find a clear pathway for attribute handling for CreateIdentity Attributes and EnsureAttributes Attributes. They seem to use in AD different set of supported attributes that can be set directly as -AttributeName parameter and via -OtherAttributes for New-ADUser, while Set-ADUser doesn't have this, but -Add, -Replace and -Remove parameters.

But basic conclusion is:

• any string for attributes in EnsureAttributes (with supported parameter in Set-ADUser, but not in list of supported attributes from CreateIdentity) leads to an error on supported attributes
• OtherAttributes, although pointed out also dont work and gives same error
• any $null value on any value to unset a value results in MethodArguments error