JacksonGenerator serializes byte[] as array of numbers

Is this the preferred behavior?

As far as I know Jackson by default encodes `byte[]` to Base64 strings, why this change? In there any point where the array of numbers representation is useful?

I am asking because this behavior forces users to do the base64 encoding by themselves when loading [BYTES](https://cloud.google.com/bigquery/data-types) data into a BigQuery table using [`TableDataInsertAllRequest`](https://developers.google.com/resources/api-libraries/documentation/bigquery/v2/java/latest/com/google/api/services/bigquery/model/TableDataInsertAllRequest.html).

Start by locating JacksonGenerator and checking how byte[] values are serialized. Compare its output with the linked BigQuery BYTES documentation and TableDataInsertAllRequest usage. Done means the intended representation is agreed and verified with a focused regression test.

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