fix: action buttons on the DAG list page don't work for DAGs with custom names

[rocwang]

When a DAG has a custom name defined, the actions buttons on the DAG list page don't work as the frontend uses the custom name instead of the DAG file name to call the "Submit DAG Action" API (POST /api/v1/dags/:name).

For example, given a DAG namely test.yaml as below:

name: Custom Name
steps:
  - name: step1
    command: echo hello

When the "Start the DAG" button is clicked from the DAG list page, the following API is called incorrectly:

POST /api/v1/dags/Custom Name.

Instead, POST /api/v1/dags/test should be called.

To fix it, I simply extract the DAG filename without the .yaml extention name from data.DAGStatus.File, and then use that as the name property on DAGActions.

[yottahmd]

✨✨✨LGTM✨✨✨, thank you very much for fixing the bug!