test: add unit tests for routes

[italojohnny]

This PR aims to lay the groundwork for changing endpoint dependencies to async, with the goal of improving API performance. To ensure that endpoints don’t break when dependencies are updated, unit tests have been created to cover the happy path for all routes that are not yet async. Additionally, these endpoints have also been converted to async.

The endpoints were identified with the following command:

grep --include="*.py" -nr "^def" -B 1 | grep "@router"

[ogabrielluiz]

You might need to remove the tests that overlap with these.
You can check test_database.py and some other files in the same level.

[ogabrielluiz]

LGTM