Ad conversions fail after a creative has expired

[tmancey]

Description

Steps to Reproduce

1. View an ad (which has a conversion)
2. Close the browser
3. Remove the campaign from the catalog

Actual result:

Ad can no longer be converted when visiting the landing page

Expected result:

Ad should be converted when visiting the landing page

Reproduces how often:

Easily reproduced

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the dev channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Miscellaneous Information: