Hello Team,
Please provide ability to read custom MIP Sdk labels using https://graph.microsoft.com/v1.0/me/messages endpoint.
There is a non-documented approach which allows to do it, however I can't use in production because it's not officially documented and supported:
https://graph.microsoft.com/v1.0/me/messages?$expand=singleValueExtendedProperties($filter=id eq 'String {00020386-0000-0000-C000-000000000046} Name msip_labels')