Fix GCSToGCSOperator behavior difference for moving single object

[boraberke]

GCSToGCSOperator did not retain the nested folder structure when moving a single object. This PR merges the logic for single and multiple objects and handles folder structure similar to what gsutil does.
closes: #37576

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[potiuk]

I think this one requires at the very least some more explanation added to https://github.com/apache/airflow/blob/main/airflow/providers/google/CHANGELOG.rst

It's on the border of breaking change, but we can also treat it as a bugfix, but we should have a user-targeted explanation on what they should do if they experience the problem. Could you please add such explanation at teh top of the Changelog?

[boraberke]

I think this one requires at the very least some more explanation added to https://github.com/apache/airflow/blob/main/airflow/providers/google/CHANGELOG.rst

It's on the border of breaking change, but we can also treat it as a bugfix, but we should have a user-targeted explanation on what they should do if they experience the problem. Could you please add such explanation at teh top of the Changelog?

Hi @potiuk, thanks for the feedback! I added a note about the change. It was a bit unclear without an example as it is a very specific case, so I also added a simple example to make it clear.

LMK if I need to change anything.

[potiuk]

nice!