Fix: cuda linking and Release jobs dependencies pulling

Context

1. Fix linking cuda dependecies to aidge_learning unit tests (issue aidge#213).
   

2. Fix : Release jobs were not testing packages with dependencies pulled from pypi. This led to :

   1. not testing if packages were compatible with online packages.
   2. Having to re compile everything from scratch twice, which led to reeeally long jobs

Modified files

• CMakeLists.txt, remove finding backend_cuda;
• unit_tests/CMakeLists.txt, link missing cudart and cublas;
• pyproject.toml, test packages with dependecies pulled from pypi