DatePicker: add `onReset` event

[silvalaura]

Is your feature request related to a problem? Please describe. Is there a way to track when the "reset" function is triggered, so we can reset our state accordingly? Currently, the code does not emit any events: (https://github.com/cengage/react-magma/blob/dev/packages/react-magma-dom/src/components/DatePicker/index.tsx#L288)

Describe the solution you'd like

• onReset event is added to the DatePicker component which gets called when the reset function is triggered