Array.prototype methods cause validation error in the expected transports[<method>] to be 'string'

Issue: as the transports validation uses in to loop through items of array it bring the method defined array through prototype.

fix: use 'of' instead of 'in' ,because 'in' iterates over all enumerable property keys of an object * including the method cause invalid validation error, "of" only iterates through the values of objects.