LookupIn does not correctly parse config returned by NMVB

The sub document API multilookup operation does not correctly handle a Not My VBucket (NMVB) response from the server.  The updated configuration from the server is not parsed correctly and the client's vbucket map is not updated.

MultiLookup<T>.GetValue attempts to interpret the beginning portion of the configuration JSON string as a body length (SDK version 2.7.13, MultiLookup.cs line 97)

This results in spikes in memory usage as an extremely large and unneed byte array is allocated, and an ArgumentException when attempting to read past the end of the response buffer.  The execption causes the response status to be changed from VBucketBelongsToAnotherServer to ClientFailure, which causes the configuration update logic to never be invoked.