Re-enable GPU tests

two gpu tests are currently disabled because they need to be fixed, please re-enable them after [insert]:


https://github.com/exasol/notebook-connector/blob/main/test/integration/gpu/itest_slct_manager_with_gpu.py
https://github.com/exasol/notebook-connector/blob/main/test/integration/gpu/test_itde_manager_with_gpu.py