Add deferrable mode to GCPToBigQueryOperator + tests

[VladaZakharova]

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[potiuk]

Needs conflict resolving after string normalization in providers.

[quentin-sommer]

Hi, I tracked an issue I have to this pr:
I'm using airflow-2.3.4

def _check_schema_fields(self, table_resource):

(In airflow/providers/google/cloud/transfers/gcs_to_bigquery.py)

is executed and try to infer a schema on my newline delimited json file. It obviously doesn't work, I end up with column names containing {".

I'm trying to understand why the function is called on all the data types without checking if source_format is 'CSV'. Maybe I'm just using it wrong? Hope you can help

I could provide the schema_fields every time to make the operator bypass the check but it was convenient to let bigquery detect the schema.

ping @VladaZakharova and @potiuk

[VladaZakharova]

@quentin-sommer
Hi Team,
I am working on preparing a PR with a fix for this issue and will share all the updates.

[VladaZakharova]

@quentin-sommer
Hi Team :)
Please, check the PR that I have created for the fix to this issue:
#28284

Thanks!