Fix/return types

[darylldoyle]

Description of the Change

This PR goes through our scaffold and adds the correct return types to methods and functions. This will increase the reliability of static analysis available to engineers, either via their IDEs or a tool like PHPStan.

Additionally, it ensures that we, as a company, are starting engineers off on the best foot possible, with no potential errors caused by incorrect return types.

Finally, there are some places where I've added additional defensive coding to ensure that we don't inadvertently trigger errors.

How to test the Change

Test the scaffold locally.

Changelog Entry

• Fixed - Return types

Credits

Props @darylldoyle

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.

[tobeycodes]

This looks good. I'd love to see in a follow up PR in the future

• Removal of mixed
• Removal of phpstan ignore errors
• Consistent return types on get_asset_info

[fabiankaegy]

Agree with all that @tobeycodes already mentioned 👍

[tlovett1]

Looks good