🔧 change logic to see if ds or table exists

[AlejandroUPC]

Description

The goal of this MR is to tackle the issue mentioned here. The explanation is pretty much there.

Implementation

Right now to check if something exists the code tries to create the dataset with the parameter exists_ok, which in the internal bigquery library it just avoids raising an Exception as documented here.

The issue is that those calls are still created on the API and then handled in code, and your logs are going to be flooded with errors in your bigquery API.

With this MR the aim is to add an extra call to get the resources (dataset or table) and handle the NotFound exception itself. There is a potential cons that is making an additional call to the API to check if the resource actually exists.

Summoning @z3z1ma @blancaruano

[z3z1ma]

LGMT, I think I need to merge it for the tests to run
Also noticed maybe a bug in the other merged branch, I will follow up