Fix draw_key_rect() not using data$fill for glyph fill (#6609)

* Fix draw_key_rect() not using data$fill for glyph fill

* Accept snapshot and update NEWS

Author: mitchelloharawild

NEWS.md

@@ -1,5 +1,10 @@
 # ggplot2 (development version)
 
+### Bug fixes
+
+* Fixed regression where `draw_key_rect()` stopped using `fill` colours 
+  (@mitchelloharawild, #6609).
+
 # ggplot2 4.0.0
 
 ## User facing

R/legend-draw.R

@@ -54,7 +54,7 @@ draw_key_abline <- function(data, params, size) {
 #' @export
 #' @rdname draw_key
 draw_key_rect <- function(data, params, size) {
-  colour <- if (is.na(data$fill %||% NA)) data$colour
+  colour <- if (is.na(data$fill %||% NA)) data$colour else data$fill
   rectGrob(gp = gg_par(
     col = NA,
     fill = fill_alpha(colour %||% "grey20", data$alpha),