#1501 [v3] Removed Extra Decorator

[k-macmillan]

Description

Removed extra decorator that prevented the Celery task from running.

Added some unrelated, but required, unit test fixes and locked pytest + moto to their last major versions due to breaking changes.

issue #1501

Type of change

Please check the relevant option(s).

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Documentation changes only

How Has This Been Tested?

Deployed and tested sending an email with v3. Succeeded.

Checklist

• I have assigned myself to this PR
• PR has an appropriate title: #9999 - What the thing does
• PR has a detailed description, including links to specific documentation
• I have added the appropriate labels to the PR.
• I did not remove any parts of the template, such as checkboxes even if they are not used
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to any documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have ensured the latest master is merged into my branch and all checks are green prior to review
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• The ticket is now moved into the DEV test column