fix: scroll only until text exits screen

Was scrolling an extra container-width of invisible distance after the
text had already left the screen, adding ~11s of dead time. Now scrolls
to -textWidthPx (text just off-screen) instead of -(textWidthPx +
containerWidthPx).

Made-with: Cursor

app/src/main/java/xyz/cottongin/radio247/ui/screens/nowplaying/NowPlayingScreen.kt

@@ -473,8 +473,7 @@ private fun TickerText(
         if (overflowPx > 0f) {
             key(text) {
                 val velocityPxPerMs = with(density) { velocityDpPerSecond.dp.toPx() } / 1000f
-                val totalScrollPx = textWidthPx + containerWidthPx
+                val scrollMs = (textWidthPx / velocityPxPerMs).toInt()
-                val scrollMs = (totalScrollPx / velocityPxPerMs).toInt()
 
                 val offset = remember { Animatable(0f) }
                 val alpha = remember { Animatable(0f) }
@@ -487,7 +486,7 @@ private fun TickerText(
 
                     while (true) {
                         offset.animateTo(
-                            -totalScrollPx,
+                            -textWidthPx,
                             tween(scrollMs, easing = LinearEasing)
                         )
                         offset.snapTo(0f)