Add GetDag endpoint to execution_api

[gopidesupavan]

related: #56954

TriggerDagRunOperator failing when the operator args sets fail_when_dag_is_paused in AF3 we are blocking the db access, but in the current TriggerDagRunOperator it still trying to use the DagModel, causing the db error. see the issue above where user explained.

here its accessing DagModel.
https://github.com/apache/airflow/blob/main/providers/standard/src/airflow/providers/standard/operators/trigger_dagrun.py#L219

Adding the GetDagState endpoint to get whether dag is paused or in active.

Fix is required for the TriggerDagRunOperator in standard provider, after this merge will add a fix.

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[gopidesupavan]

Not sure we can treat this as bugfix and backport to v3-1.

[ashb]

@gopidesupavan @kaxil Rather than a seaprate check, how about adding this as a parameter to the existing TriggerRun message and API endpoint -- and then if the dag is paused the API could return an error (412 Precondition Failed for giggles?) which could then be returned to the task code

[gopidesupavan]

@gopidesupavan @kaxil Rather than a seaprate check, how about adding this as a parameter to the existing TriggerRun message and API endpoint -- and then if the dag is paused the API could return an error (412 Precondition Failed for giggles?) which could then be returned to the task code

Yeah thats also an option good thought, but for now there is no-way if anyone wants to see dag status. not sure is it worth adding this endpoint or not. am happy to make a change if this is not required.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 5 days if no further activity occurs. Thank you for your contributions.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 5 days if no further activity occurs. Thank you for your contributions.

[gopidesupavan]

can i have review please?

[kaxil]

Nice work on the full stack implementation — endpoint, Cadwyn versioning, client, supervisor, comms, and task runner are all properly wired up. A few things to clean up before merge.

[kaxil]

All 7 previous comments addressed — looks good. One remaining nit from the test file.