Rename the concept of user-facing "Active" DAG in UI & API

[kaxil]

Same as #39593 but given we are now releasing Airflow 3.0 we can change this in a backwards-incompatible way.

Apart from just the UI, we need to change the filter in the API too. Example, we have only_active filter in "List DAGs" endpoint: https://airflow.apache.org/docs/apache-airflow/stable/stable-rest-api-ref.html#operation/get_dags

[kaxil]

Some suggestions from the Dev call on 8th August:

• @dstandish : Unpaused & Paused.
• @bbovenzi : Enabled/paused
• @ashb 's comment: I like pause/unpaused, stale (vs not stale, but not stale doesn’t really show up anywhere) for the states/values in API and DB. (Or paused/enabled is free to if “stale” is the state for dags-where-file-doesn’t-exist anymore)

cc @eladkal

[dstandish]

I think it might be helpful to consider UI and API independently.

First question, what functionality do we want in the UI?

I think I always assumed that it just meant paused vs unpaused.

And, if you don't have orphaned dags, that is acutally true, I think.

Here's a proposal. Just add one more category: "missing" a.k.a. "orphaned" a.k.a. "inactive"

And then you just have 4 categories: all, enabled, disabled, missing

Enabled / disabled seems like better terminology than paused / unpaused. Paused vs unpaused makes less sense for unscheduled dags.

[bbovenzi]

I am playing around with renaming it in the new UI. I still not sure exactly what to put: