Function: getEditingCustomRangePosition()

function getEditingCustomRangePosition(
   injector, 
   unitId, 
   subUnitId, 
   row, 
   col, 
   rangeId): null | {
  customRange: ICustomRange<Record<string, any>>;
  label: string;
  rects: undefined | {
     bottom: number;
     left: number;
     right: number;
     top: number;
    }[];
}