DirectIOART: temporary fix RDO input athena tests
Temporary fix of ART test test_directioart_athena_recotf_with_rdo_davs.sh
(and the equivalent root and https test) which process remote RDO inputs in serial athena mode as discussed in ATLASRECTS-7096.
With this update the tests are not testing anymore remote inputs in MT mode in the master branch. This will be fixed with separate new tests in a later MR.