fix: 'countries' parameter is never used

[DaniilPavlenko]

The App() function has the countries parameter with a default argument countries().

kotlin-multiplatform-dev-docs/topics/compose-onboard/compose-multiplatform-new-project.md

Line 322 in 5312b06

fun App(countries: List<Country> = countries()) {

But it is never used in the function.

kotlin-multiplatform-dev-docs/topics/compose-onboard/compose-multiplatform-new-project.md

Lines 344 to 352 in 5312b06

	countries().forEach { (name, zone) ->
	DropdownMenuItem(
	text = { Text(name)},
	onClick = {
	timeAtLocation = currentTimeAt(name, zone)
	showCountries = false
	}
	)
	}