[TEST] pre check download service working

Seen during CI tests, it could appears that the download service is not available for any reason.

This fix in test will check before each test which requires an internet access (annotated with @Network) that the download service we are testing is still working.

It won't fail the test but will mark the test as `Ignored` in case of failure.
(cherry picked from commit 2af19a4)
(cherry picked from commit 099142c)