[telemetry] add GDPRBot to classify events at PR time

[hemarina]

https://devdiv.visualstudio.com/DevDiv/_wiki/wikis/DevDiv.wiki/46339/GDPR-Bot?anchor=onboarding

[hemarina]

We already have classification in https://dev.azure.com/devdiv/DevDiv/_build?definitionId=27989&_a=summary