Replace all clippy::unwrap_used with Results and ? in all tests.

[dessalines]

Requirements

• Is this a feature request? For questions or discussions use https://lemmy.ml/c/lemmy_support
• Did you check to see if this issue already exists?
• Is this only a feature request? Do not put multiple feature requests in one issue.
• Is this a backend issue? Use the lemmy-ui repo for UI / frontend issues.
• Do you agree to follow the rules in our Code of Conduct?

Is your proposal related to a problem?

In most of our tests, we use clippy::unwrap_used annotation, when these aren't necessary.

Describe the solution you'd like.

They can be replaced with -> LemmyResult<()> (or another result type), and use ? in place of unwrap

Describe alternatives you've considered.

NA

Additional context

#5048

[Nutomic]

This is a good issue for new contributors to get started. You basically need to follow these steps:

1. Setup local dev environment
2. Search for clippy::unwrap_used in the code and remove it one at a time
3. Run ./scripts/lint.sh and fix errors one at a time by replacing .unwrap() with ?, and changing function return type to LemmyResult<()>
4. Commit frequently whenever it is compiling without errors
5. Repeat from 2

Its not necessary to remove all occurences in a single pull request, doing only part of them is also helpful. There are some cases where unwrap is used for Option, these can probably remain.