BB2-3470: Redirect to swagger UI on deny authorization

[stiwarisemanticbits]

JIRA Ticket:
BB2-3470

What Does This PR Do?

Currently when user authorizes on swagger UI and on consent screens if they click on cancel then UI shows blank page.
This PR redirects back to swagger UI page on cancel

What Should Reviewers Watch For?

If you're reviewing this PR, please check for these things in particular:

Validation

1. Start web server locally
2. Go to http://localhost:8000/
3. Click on API Reference
4. On Swagger UI page, Click on Authorize, and enter relevant details and click on Authorize
5. Enter medicare.gov login credentials
6. On Authorization screen, click on cancel instead of continue
7. It should be redirected to Swagger UI page. Before this PR it was showing blank page

What Security Implications Does This PR Have?

Please indicate if this PR does any of the following:

• Adds any new software dependencies
• Modifies any security controls
• Adds new transmission or storage of data
• Any other changes that could possibly affect security?

• Yes, one or more of the above security implications apply. This PR must not be merged without the ISSO or team
  security engineer's approval.

Any Migrations?

• Yes, there are migrations
  • The migrations should be run PRIOR to the code being deployed
  • The migrations should be run AFTER the code is deployed
  • There is a more complicated migration plan (downtime,
    etc)
• No migrations

[jimmyfagan]

Tested, and it works as expected. Looks good to me!