Adjust FlatLafDark tab-switcher and selection foreground colors

 - use context menu colors for tab switcher popup
 - set selection foreground to white
 - slightly brighten foreground color for more contrast

platform/o.n.swing.laf.flatlaf/src/org/netbeans/swing/laf/flatlaf/FlatDarkLaf.properties

@@ -18,6 +18,8 @@
 nb.dark.theme=true
 nb.preferred.color.profile=FlatLaf Dark
 
+@foreground=#cccccc
+@selectionForeground=#ffffff
 
 nb.errorForeground=#DB5860
 nb.warningForeground=@foreground
@@ -90,6 +92,11 @@ nb.multitabs.project.8.background=rgb(107, 135, 38)
 nb.multitabs.project.9.background=rgb(118, 89, 135)
 nb.multitabs.project.foreground=#f0f0f0
 
+#---- Tab switcher ----
+
+nb.popupswitcher.background=$MenuItem.background
+nb.popupswitcher.selectionForeground=$List.selectionForeground
+nb.popupswitcher.selectionBackground=$List.selectionBackground
 
 #---- PropSheet ----