Fix: bigquery.create NullPointerException when job already exists

[Lumenol]

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Fixes #3034 ☕️

[google-cla]

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[Lumenol]

It seems that mvn com.coveo:fmt-maven-plugin:format has made significant changes to the files. I'm not used to contributing, so feel free to provide feedback if it doesn't suit your preferences.

[PhongChuong]

Thanks for contributing.
I've updated the PR comments to follow a more standard convention, I hope you don't mind.

[PhongChuong]

Thank you for contributing.