Allow importing licenses with a missing "usage" attribute

[phess]

SUMMARY

This trivial change fixes AAP-14614.
The original issue happens when AAP is pulling a subscription from Red Hat Satellite, and the subscription is missing a "usage" attribute.
Many subscriptions lack a "usage" attribute, so this shouldn't cause AAP to fail with an error 400.

The error on AAP is a KeyError thrown by sub['usage'].
The fix here is to allow this lookup to return a blank value with sub.get('usage') so the KeyError is never raised and the subscription import occurs just fine.

ISSUE TYPE

• Bug, Docs Fix or other nominal change

COMPONENT NAME

• Other

AWX VERSION

No make installed in this lab AAP, so here is the RPM version.

automation-controller-venv-tower-4.4.1-1.el9ap.x86_64

ADDITIONAL INFORMATION

Logged in tower.log before this fix:

2023-08-08 18:32:14,015 ERROR    [db1442fb0fc440bdba589c6a90bd10f5] awx.api.views.root Invalid subscription submitted.
Traceback (most recent call last):
  File "/var/lib/awx/venv/awx/lib64/python3.9/site-packages/awx/api/views/root.py", line 194, in post
    validated = get_licenser().validate_rh(user, pw)
  File "/var/lib/awx/venv/awx/lib64/python3.9/site-packages/awx/main/utils/licensing.py", line 231, in validate_rh
    json = self.get_satellite_subs(host, user, pw)
  File "/var/lib/awx/venv/awx/lib64/python3.9/site-packages/awx/main/utils/licensing.py", line 290, in get_satellite_subs
    license['usage'] = sub['usage']
KeyError: 'usage'
2023-08-08 18:32:14,016 WARNING  [db1442fb0fc440bdba589c6a90bd10f5] awx.api.generics status 400 received by user admin attempting to access /api/v2/config/subscriptions/ from 10.2.69.13
2023-08-08 18:32:14,023 WARNING  [db1442fb0fc440bdba589c6a90bd10f5] django.request Bad Request: /api/v2/config/subscriptions/

Logged after the fix:
Nothing logged at INFO level or worse.

[shanemcd]

Hi @phess - please update the PR title and commit message to follow the guidelines outlined here: https://github.com/ansible/awx/blob/devel/CONTRIBUTING.md#submitting-pull-requests

Specifically, this link: How to write a Git commit message.

[rooftopcellist]

Agreed, we should merge this. For extra context, here is an example of a subscription with Usage empty:

Subscription Name:   Red Hat Ansible Automation Platform, Standard (100 Managed Nodes)
Provides:            Red Hat Ansible Automation Platform
                     Red Hat Ansible Engine
                     Red Hat Single Sign-On
                     JBoss Enterprise Application Platform
SKU:                 MCT3691
Contract:            12856738
Pool ID:             8a85f99c7d76f2fd017d96c9f1e606bb
Provides Management: No
Available:           431
Suggested:           1
Service Type:        L1-L3
Roles:               
Service Level:       Standard
Usage: