dismiss the now playing overlay when playback is cleared

app/src/main/kotlin/com/subtracks/ui/AppRoot.kt

@@ -136,6 +136,13 @@ private fun MainNavigation() {
     LaunchedEffect(Unit) { if (nowPlayingOpen) nowPlayingProgress = 1f }
 
     val playerVisible = playback.item != null
+    LaunchedEffect(playerVisible) {
+        if (!playerVisible) {
+            settleJob?.cancel()
+            nowPlayingOpen = false
+            nowPlayingProgress = 0f
+        }
+    }
     val density = LocalDensity.current
     val navBarInset = with(density) { WindowInsets.navigationBars.getBottom(this).toDp() }