Expose PickerProps and PickerItemProps types

[amiratak88]

Feature request

Expose PickerProps and PickerItemProps types in the declaration files

Why it is needed

I'm trying to write a wrapper for this so it works similarly to how a select tag works in iOS (which is a good feature to add in itself IMO) and need to accept these props for that wrapper.

This is what I'm doing at the moment.

import { PickerProps } from 'node_modules/@react-native-community/picker/typings/Picker';

[amiratak88]

I was able to get the type using TypeScript's ConstructorParameters utility type which is a safer alternative.

import { Picker } from '@react-native-community/picker';
type PickerProps = ConstructorParameters<typeof Picker>[0];