[py] GRPC routing metadata is incorrectly computed for update calls

[bdhess]

As an example:
https://github.com/googleapis/google-cloud-python/blob/de73e45a7183a638113153d0faec105cfc437f0e/kms/google/cloud/kms_v1/gapic/key_management_service_client.py#L1569

When the crypto_key argument to UpdateCryptoKey is a dict, the attempt to resolve crypto_key.name results in an AttributeError ("'dict' object has no attribute 'name'"). The error is caught and ignored, so this fails silently.

Reported by a customer at https://stackoverflow.com/questions/59617920/cant-update-cryptokey-in-us-central1

[BinarSkugga]

The bug also happens with UpdateCryptoKeyVersion

[hkdevandla]

@software-dov , can you clarify if this issue happens in the micro-generator or is this something that we should fix in the current gapic?

[arithmetic1728]

I think this bug only applies to the monolith generator. The issue is that monolith generator generated code takes individual fields, since one of the field can be either a dict or an object, but the code doesn't handle dict well, it throws exceptions. micro-generator doesn't allow users to provide fields separately, instead they have wrap the fields in a request object, so it won't have this issue.

The following is an example demonstrating this.

micro-generator generated echo method:
https://github.com/arithmetic1728/showcase_sample/blob/master/showcase_generated/google/showcase_v1beta1/services/echo/client.py#L140

monolith generator generated echo method:
https://github.com/arithmetic1728/showcase_sample/blob/master/showcase-monolith/google/showcase_v1beta1/gapic/echo_client.py#L211