Bug-fix justification with angle in geom_label() (#5424)

Now that geom_label() supports rotation with angle, it is necessary to pass the angle as the third argument to compute_just() as it is done in geom_text() to ensure correct text justification.

R/geom-label.R

@@ -74,10 +74,10 @@ GeomLabel <- ggproto("GeomLabel", Geom,
 
     data <- coord$transform(data, panel_params)
     if (is.character(data$vjust)) {
-      data$vjust <- compute_just(data$vjust, data$y)
+      data$vjust <- compute_just(data$vjust, data$y, data$x, data$angle)
     }
     if (is.character(data$hjust)) {
-      data$hjust <- compute_just(data$hjust, data$x)
+      data$hjust <- compute_just(data$hjust, data$x, data$y, data$angle)
     }
     if (!inherits(label.padding, "margin")) {
       label.padding <- rep(label.padding, length.out = 4)