[ Merge of http://go/wvgerrit/87905 ]
Protobuf parsing of the provisioning message has been centralized in
certificate_provisioning.cpp since it will be invoked from
multiple locations. This will also ease maintainability of the code.
Bug: 142731300
Test: android unit/integration tests
Change-Id: Idebf6b0145b317698559cac1cf18a3a0b98315ad
8769e12b01