* refactor: move tests folder to src/backend
* chore(Makefile): update pytest commands to run tests from the correct directory paths for unit and integration tests
* refactor: update file path in test_custom_component.py
The file path in the test_custom_component.py file has been updated to use the correct relative path to the component_multiple_outputs.py file. This change ensures that the test code can access the correct file and improves the reliability of the test.
