Some pages are missing callback examples #61
Description
Skimmed over some pages and noticed that eg. Slider and Date/TimePicker are not hooked up to any state on the page - interacting with them doesn't result in any changes to the app page. I think this is how those controls get used primarily.
Suggestion: add some dynamic text that is altered by interactions with those components.
(+nit: the first Pressable example is missing an onPress callback)