Async Insecure Client

[Sjhunt93]

When using the InsecureClient it does not correctly create async channel. After establishing a channel with fake_credentials the following code defaults to using a sync connection:

insecure_channel = grpc.insecure_channel(target, options, compression)

The class method create_channel switches automatically between grpc. and grpc.aio. Should this behaviour also apply in the insecure client?

[Sjhunt93]

async def rr():

    client = Client(
        "localhost:50051",
        insecure_bearer_token_credentials("123")
    )

    post_one = ObjectReference(object_type="org/brief", object_id="1")
    emilia = SubjectReference(object=ObjectReference(
        object_type="org/tag/user",
        object_id="emilia",
    ))

    resp = await client.CheckPermission(CheckPermissionRequest(
        resource=post_one,
        permission="viewer",
        subject=emilia,
    ))
    assert resp.permissionship != CheckPermissionResponse.PERMISSIONSHIP_HAS_PERMISSION

# force async loop
asyncio.run(rr())

The above works as expected

Running the same but with:

    client = InsecureClient(
        "localhost:50051",
        "123"
    )

results in:

TypeError: object CheckPermissionResponse can't be used in 'await' expression

[tstirrat15]

I'll have a look at this.

[tstirrat15]

I've got a PR in progress... the python gRPC client makes this a pain.

[tstirrat15]

Related to grpc/grpc#33618