Remove Invalid Get-Mg*AvailableExtensionProperty commands

[peombwa]

This PR closes #724 by applying command suppression directive to remove the following invalid Get-Mg*AvailableExtensionProperty commands from the affected modules:

Name	Module
Get-MgApplicationAvailableExtensionProperty	Microsoft.Graph.Applications
Get-MgContactAvailableExtensionProperty	Microsoft.Graph.Identity.DirectoryManagement
Get-MgContractAvailableExtensionProperty	Microsoft.Graph.Identity.DirectoryManagement
Get-MgDeviceAvailableExtensionProperty	Microsoft.Graph.Identity.DirectoryManagement
Get-MgDirectoryRoleAvailableExtensionProperty	Microsoft.Graph.Identity.DirectoryManagement
Get-MgDirectoryRoleTemplateAvailableExtensionProperty	Microsoft.Graph.Identity.DirectoryManagement
Get-MgGroupAvailableExtensionProperty	Microsoft.Graph.Groups
Get-MgOrganizationAvailableExtensionProperty	Microsoft.Graph.Identity.DirectoryManagement
Get-MgServicePrincipalAvailableExtensionProperty	Microsoft.Graph.Applications
Get-MgUserAvailableExtensionProperty	Microsoft.Graph.Users.Actions

As per the docs, only Get-MgDirectoryObjectAvailableExtensionProperty should be generated,