Follow up to #2527

This updated errors from grpc single-shot uploads to have messages that include useful debugging information.

When a response is received but doesn't validate with the expected state:
```
com.google.cloud.storage.StorageException: Finalized upload, but object size less than expected.
	|> [
	|> 	com.google.storage.v2.WriteObjectRequest{
	|> 		write_offset: 524288
	|> 		finish_write: true
	|> 	}
	|> ]
	|
	|< com.google.storage.v2.WriteObjectResponse{
	|< 	resource {
	|< 	  name: "obj"
	|< 	  size: 262144
	|< 	}
	|< }
	|
```