fix: dag_run_dag_id_execution_date_key

[raphaelauv]

fix: #38176

[Taragolis]

For avoid accidentally merge

This was discussed into the Dev List into the past, there is no consensus about this remove uniques of execution date, see:
[DISCUSS] Allowing Multiple DAG Runs with the Same Execution Date

So I would rather create a new discussion in dev list first

[hussein-awala]

I was actively working on this, but found some tables that only use execution date as the primary key (without dag run id), so we need to migrate them first before removing the unique constraint on execution date. I will create an issue with all the details in the coming weeks.

[github-actions]

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[raphaelauv]

#41818