Override default task queue for activity doesn't work about protoc-gen-go-temporal HOT 1 CLOSED

Hi @cludden, this solution #39 not some correctly, because activity task_queue not overriding when not using activity options (third args) and options gets from ctx.

sample case:

• default in workflow context included workflow task_queue and activity not overided queue because task_queue alreade defined (options allready included in context and/or use default activity options from deifined in proto)

func TestActivityTaskQueue2(t *testing.T) {
	require := require.New(t)

	var suite testsuite.WorkflowTestSuite
	env := suite.NewTestWorkflowEnvironment()
	simplepb.RegisterSimpleActivities(env, &testActivitiesTQ{})

	env.ExecuteWorkflow(func(ctx workflow.Context) error {
		_, err := simplepb.SomeActivity3(ctx , &simplepb.SomeActivity3Request{
			RequestVal: "foo",
		})
		require.NoError(err)
		return nil
	})
	require.True(env.IsWorkflowCompleted())
	require.NoError(env.GetWorkflowError())
}

expecting activity run in specific queue (writen in proto) not workflow queue

so need forced overide task_queue if this define in proto:

- if opts.opts.TaskQueue == "" {
    opts.opts.TaskQueue = "some-other-task-queue"
- }

from protoc-gen-go-temporal.