Invalid 2D sphere documents do not throw BadValue

The jsTest timeseries_metric_index_2dsphere.js asserts that ErrorCodes::BadValue is thrown when invalid documents are provided. However, the code does not throw this error code. This hasn't been caught because the loop used to check these documents is incorrect, and is inserting the indices of the document (because of how for/in loops work in javascript) which are currently just ignored by the bulk insert api.