In C++ APIView, Unspecified access modifier for classes should be considered private and not visible, rather than public

For example, `m_uniqueAddress` is a private member and shouldn't show up in APIView :
https://apiview.dev/Assemblies/Review/3226949419594af785233c8289dd76ef?diffRevisionId=ff4751148eca42aab49b605affd2f040&doc=False&diffOnly=False&revisionId=e32c070b6c9e473d84e6cef78f05d3bd


https://github.com/Azure/azure-sdk-for-cpp/blob/39d1b844ef3e9bf741ecafb5ca93b445b33608f0/sdk/core/azure-core/inc/azure/core/context.hpp#L46-L47

https://github.com/Azure/azure-sdk-for-cpp/blob/39d1b844ef3e9bf741ecafb5ca93b445b33608f0/sdk/core/azure-core/inc/azure/core/operation_status.hpp#L24-L25

The workaround is relatively simple here, and we can mark the access modifier in source, explicitly.

cc @RickWinter, @LarryOsterman

Start with the C++ APIView output for sdk/core/azure-core/inc/azure/core/context.hpp and operation_status.hpp, focusing on how unspecified class access is represented. Compare those declarations with the linked APIView review and verify that private members such as m_uniqueAddress are no longer visible without an explicit source modifier.

Written by the indexing model from the issue text.