Draft: Test(artifact): Add expected compute output to test_plugin (#57)
Add expected_compute_output to the plugin, which was missing so far. So that now not only the artifact content is tested (which was already the case), but also the metadata (e.g. description, legend, summary, etc.). This should fulfill the testing requirements for the reactivation of the artifact descriptions (?)
For the LULC classification artifacts, I will add the legends to the expected_compute_output once they are implemented correctly.