Fix the losscalculator to accept more mappings than needed

This issue is to fix the bug with description as below:
If the input intensity_measure_map.csv which is one of the optional inputs is used to run a damage calculation using the losscalculator, contain more mapping than it is used in the calculations, it throws an error!
This also means that since the default value contains many possible mappings, in case of having a computations that for example does not use 'MMI' in the calculations, can not use the default value!

This input has the default value as below:

in_fragility_function, in_ground_motion_field
SA(0.3),gmv_SA(0.3)
SA(0.6),gmv_SA(0.6)
SA(1),gmv_SA(1.0)
SA(1.0),gmv_SA(1.0)
PGA,gmv_PGA
MMI,gmv_MMI