Fix BigQueryCursor execute method if the location is missing

[e-galan]

This addresses a bug where BigQueryValueCheckOperator tasks failed if it was not provided with the location parameter and the dataset location was outside of the US.

If the location parameter is not provided to BigQueryValueCheckOperator, then the location parameter will still be None when execution reaches the BigQueryCursor execute method. The execute method makes two client requests: the first to the BigQuery client, which can work without the location provided, the second to the Google Discovery client, which cannot find a resource without the location resulting in a error.

Pulling the location from a successful BigQuery request result resolves that problem.

Change list:

• Make BigQueryCursor use the job location in the case when the location is not provided during the cursor's instantiation.
• Update typing and docstrings.

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[dirrao]

is it feasible to add the test case for the bug?
Can you fix the failing static checks?

[e-galan]

is it feasible to add the test case for the bug? Can you fix the failing static checks?

@dirrao I can add a unit test, but it will be totally dependent on mocks, because the problem happens between the two client requests. Will that do?

I can't fix the static check, it fails because of smth that does not seem related to my PR:

[Taragolis]

This static check failure not relevant your PR, it will be fix (at least temporary) by #39662

[eladkal]

@dirrao I can add a unit test, but it will be totally dependent on mocks, because the problem happens between the two client requests. Will that do?

We have system tests for google so probably we should modify/add coverage there. @VladaZakharova WDYT?

[VladaZakharova]

@eladkal
Yes, thank you , will be good to add system test here to cover this scenario: f.e. try to create dataset and table with location different from US and then run BigQueryValueCheckOperator without specifying location.

@e-galan Please, add the changes accordingly

[e-galan]

I have added the system test @dirrao @eladkal . Please take a look.

[VladaZakharova]

Hi @eladkal @potiuk !
I guess we have made all the changes, can you please take a look again? :)

[eladkal]

LGTM