add proxyemail attribute to Azure Active Directory Domain Services AADDS for LDAPs queries

Currently it is not possible to read the proxyemail from the azure active directory domain services. we want to use this for a third party AV/AS mail solution. we got the following feedback from the PG 

“This is expected. ProxyEmail is not an attribute that is currently synced to AAD DS. This field will be empty and cannot be used in LDAPs query.”