fix(icons): making caching last step of syncBreaches job

[joeherm]

References:

Jira: MNTOR-5251

Description

• We are overwriting the Redis cache key in syncJobs before we've fetched logos
• Move caching to be the final step of the cron

Screenshot (if applicable)

Not applicable.

How to test

• I looked into Redis in staging and none of the entries have a favicon_url
• Running locally the script now populates favicon_url in Redis
• Added unit tests to catch potential issues in the future

Checklist (Definition of Done)

• Localization strings (if needed) have been added.
• Commits in this PR are minimal and have descriptive commit messages.
• I've added or updated the relevant sections in readme and/or code comments
• I've added a unit test to test for potential regressions of this bug.
• If this PR implements a feature flag or experimentation, I've checked that it still works with the flag both on, and with the flag off.
• If this PR implements a feature flag or experimentation, the Ship Behind Feature Flag status in Jira has been set
• Product Owner accepted the User Story (demo of functionality completed) or waived the privilege.
• All acceptance criteria are met.
• Jira ticket has been updated (if needed) to match changes made during the development process.
• Jira ticket has been updated (if needed) with suggestions for QA when this PR is deployed to stage.

[Vinnl]

Oof, that's a bunch of mocking, what a hassle 😅