Deactivating an active DAG has no deactivation indicator in UI

Apache Airflow version

Other Airflow 3 version (please specify below)

If "Other Airflow 3 version" selected, which one?

3.1.6

What happened?

When deactivating a DAG by removing it from the DAGS_FOLDER, you can still access it on the UI by visiting its old URL.

However there is no indication that the DAG was deactivated. Additionally, if it was active before deletion:

its state is still active
a Next Run datetime is displayed

What you think should happen instead?

The UI should indicate that the DAG has been deactivated.

How to reproduce

remove a an active DAG from DAGS_FOLDER
await DAG processing
open the now deactivated DAG's UI via its URL

Operating System

Linux via the standard docker-compose file

Versions of Apache Airflow Providers

apache-airflow-providers-amazon==9.19.0
apache-airflow-providers-celery==3.15.0
apache-airflow-providers-cncf-kubernetes==10.12.0
apache-airflow-providers-common-compat==1.11.0
apache-airflow-providers-common-io==1.7.0
apache-airflow-providers-common-messaging==2.0.1
apache-airflow-providers-common-sql==1.30.2
apache-airflow-providers-docker==4.5.1
apache-airflow-providers-elasticsearch==6.4.2
apache-airflow-providers-fab==3.1.1
apache-airflow-providers-ftp==3.14.0
apache-airflow-providers-git==0.2.0
apache-airflow-providers-google==19.3.0
apache-airflow-providers-grpc==3.9.1
apache-airflow-providers-hashicorp==4.4.1
apache-airflow-providers-http==5.6.2
apache-airflow-providers-microsoft-azure==12.10.1
apache-airflow-providers-mysql==6.4.0
apache-airflow-providers-odbc==4.11.0
apache-airflow-providers-openlineage==2.9.2
apache-airflow-providers-postgres==6.5.1
apache-airflow-providers-redis==4.4.1
apache-airflow-providers-sendgrid==4.2.0
apache-airflow-providers-sftp==5.5.1
apache-airflow-providers-slack==9.6.1
apache-airflow-providers-smtp==2.4.1
apache-airflow-providers-snowflake==6.8.1
apache-airflow-providers-ssh==4.2.1
apache-airflow-providers-standard==1.10.2

Deployment

Official Apache Airflow Helm Chart

Deployment details

Docker-Compose

Anything else?

No response

Are you willing to submit PR?

Yes I am willing to submit a PR!

Code of Conduct

I agree to follow this project's Code of Conduct

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