Wrong onEndReachedThreshold for ListView

[seblau]

The ListView component specifies an onEndReachedThreshold of 40 (see: https://github.com/shoutem/ui/blob/develop/components/ListView.js#L142) which is invalid since this value should be in the range from 0 to 1 (see https://reactnative.dev/docs/flatlist#onendreachedthreshold).

The value of 40 causes the onEndReached callback to be triggered indefinitely in a loop.