Fix Current Card BOM

[aimthiazz]

The Current Card BOM has 4 current sensors instead of 1 (See attached image). This needs to be fixed.

[npetersen2]

Thanks @aimthiazz

This is caused by the following:

1. the Supplier Part Number 1 field in Altium is blank for a component
2. the BOM is exported with "group by Supplier Part Number 1" selected

This means that, in Altium, the LEM sensor is indeed NOT specified 4 times, but instead, that the LEM sensor has no P/N specified.

TODO

The real TODO here is:

1. Update the LEM sensor P/N to be valid
2. Mark the TitleBlockWEMPEC schematic symbol to NOT be included in the autogenerated BOM (i.e. "Graphical" component)
3. Mark the M3 schematic symbol to be "Mechanical" only, i.e. still goes to the PCB layout, but not included in the BOM. This is correct since the M3 refers to the MH1 and MH2 which are mounting holes. These should not be in the BOM!
4. Re-export the BOM from Altium and update in this repo