Release the weighted slot to centre a cluster

A row holding a sized-by-content block, a gap and a fixed button, meant to read as one cluster:

Row(
    horizontalArrangement = Arrangement.Center,
    modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp),
) {
    BoxWithConstraints(Modifier.weight(1f, fill = false)) {
        // caps each item at a maximum width, so with few items it draws narrower than maxWidth
        TabCapsule(availableWidth = maxWidth, tabs = tabs)
    }
    Spacer(Modifier.size(12.dp))
    Box(Modifier.size(56.dp)) { SearchButton() }
}