Check if `detectors_file_updated` can be written at the beginning

I just got this error message due to a missing folder:

|14:20:44.995|   (FATAL) Error during execution of run:
                          Cannot create detectors file /home/lachnit/dSiPM_TB2/run_ana/geo/mimosa_dsipm_dut_aligned.geo
                         Please check your configuration and modules! Cannot continue...

Unlucky part: this happened after the alignment. While the shift is still shown, this check should probably happen at the beginning, not at the end.