tests: add retry in prometheus config pickup test
tests: add retry in prometheus config pickup test

We don't know exactly when the prometheus chain will pick up
our config, so let's retry few times before to give up and fail.

Signed-off-by: Francesco Romani <c7100b580e6017ef67482ace46578cdd2d2e0dfe@redhat.com>

stu-gott/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt