EventLoaderTimepix3: bugfix for missing plane data
Ignore power pulsing headers for all detectors, except the DUT. Previously this was the other way around, so that data from telescope planes was not read after a corrupt header 0x0. This affected many runs in the November 2018 test-beam data taking. Note that the power-pulsing code is probably anyway outdated, as Estel used a different branch.