703 Added RECAP Fetch webhook event

[albertisfu]

This PR adds support for RECAP Fetch webhook events as commented in #703.

The webhook event has the following structure:

{
   "payload":{
      "id":803712,
      "court":null,
      "docket":null,
      "recap_document":221797284,
      "date_created":"2023-01-06T09:06:23.854208-08:00",
      "date_modified":"2023-01-06T09:06:24.760189-08:00",
      "date_completed":"2023-01-06T09:06:24.760078-08:00",
      "status":2,
      "request_type":2,
      "message":"Successfully completed fetch and save.",
      "pacer_case_id":"",
      "docket_number":"",
      "de_date_start":null,
      "de_date_end":null,
      "de_number_start":null,
      "de_number_end":null,
      "show_parties_and_counsel":true,
      "show_terminated_parties":true,
      "show_list_of_member_cases":false
   },
   "webhook":{
      "version":1,
      "event_type":3,
      "date_created":"2022-12-28T14:21:40.855097-07:00",
      "deprecation_date":null
   }
}

Is triggered when the fetch task is marked as completed when one of the following statuses:

SUCCESSFUL, FAILED, INVALID_CONTENT, or NEEDS_INFO

Webhook events are not triggered on the following statuses:
ENQUEUED, IN_PROGRESS, or QUEUED_FOR_RETRY

• Added documentation for this new webhook event.
• Added dummy webhook data to send webhook test events.

Working on this I detected some bugs and changes that were needed:

• Removed mark_fq_status (SUCCESSFUL) at the end of fetch_docket to avoid duplicated webhook events since there is a mark_fq_successful task within do_pacer_fetch for fetch docket chain.
• I found a bug within fetch_docket task, when cookies expired the fq object was marked as failed but the task execution and following tasks in the chain continue. When the task and consecutive tasks in the chain should be aborted, I solved it by returning None if there are no cookies. The reason tests were not catching this problem is that within a test all the tasks in a chain are executed so the mark_fq_successful task was being executed even though the fetch failed.
• Fixed tests for RecapDocketFetchApiTest adding a mock for cookies and adding an additional assert that checks if a RECAPDocument is created when fetching the docket instead of only relying on the FQ SUCCESSFUL status.
• I found what seems to be another bug, when fetching a docket only by pacer_case_id and court it was not working since the pacer_case_id provided in the requests was not being used, so I added it in the first place here: tasks.py#L1695, so that if the pacer_case_id is passed in the fetch request it'll be used. The test for this test_fetch_docket_by_pacer_case_id was not failing for the same reason described above related to mark_fq_successful task. So I also added an additional assert to confirm the docket is properly fetched.

Let me know what you think.

[mlissner]

A couple small tweaks, please. I also pushed some updates to the docs that you'll see.

[albertisfu]

Thank you! I've applied the requested changes.

The one related to moving send_recap_fetch_webhook_event is applied on #2456 that I set to be merged into this one.

[mlissner]

Just merged the refactor into this one. Let me know when you feel good about this one if you don't already.

[albertisfu]

Thanks for your comments, I have applied the suggestion and this seems ready!