AuthenticationStoreTokenCace.CacheData should come from the serialized data in the ADAL TokenCache

[markcowl]

Description

As seen here: https://github.com/Azure/azure-powershell/blob/preview/src/Common/Commands.Common.Authentication/Authentication/AuthenticationStoreTokenCache.cs When the CacheData proeprty is set or retrieved, the data simply comes from an internal byte array. Instead, the data should come from and be stored in the ADAL TokenCache using the Serialize and Deserialize methods

• Update CacheData getter in AuthenticationStoreTokenCache to use base.Serialize() to get the token cache data and ensure it is written to the store
• Update CacheData setter in AuthenticatioNStoreTokenCache to use base.Deserialize to consume new serialized Cache data as well as write it to the store.
• Add a live test to verify correct serialization

Cost: 2

[markcowl]

Fixed