Fix cursor unique name surpasses Postgres identifier limit in PostgresToGCSOperator

[dybolo]

closes: #37654

The function unique_name now generates UUID from the SHA-1 hash using the dag id and the task id. The previous version of the function throwed unterminated quoted identifier error when the operator was used with a task_id greater than 24 bytes as the name generated surpassed the postgres identifier limit.

[boring-cyborg]

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[potiuk]

@Taragolis ?

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.