Remove CAMEL_K_TEST_SKIP_PROBLEMATIC flag

[squakez]

For some reason, in the past, this flag was introduced as we were not able to solve certain checks failing in Openshift (likely in certain downstream builds). This can be misleading, as all tests are meant to work correctly in upstream CI. If some check is failing in any Kubernetes distribution, we should instead identify the root cause and solve it.

I advocate to remove the flag and all inherent to it, and bubble up any problem in order to be properly addressed instead of leaving it unattended for years (like it is happening now).

[squakez]

cc @lburgazzoli