fix(colors): fix tab identity blue color

The usage of the accent color variable seems like a left over from the times when multiple accents dind't exist and "accent" was an alias for "gnome blue".

Fixes #1045

Author: rafaelmardojai

theme/colors/dark.css

@@ -37,6 +37,7 @@
 		--gnome-toolbar-icon-fill: #ffffff;
 
 		/* Tabs */		
+		--gnome-tabbar-identity-color-blue: #81d0ff;
 		--gnome-tabbar-identity-color-green: var(--gnome-palette-green-1);
 		--gnome-tabbar-identity-color-yellow: var(--gnome-palette-yellow-2);
 		--gnome-tabbar-identity-color-orange: var(--gnome-palette-orange-3);

theme/colors/light.css

@@ -139,7 +139,7 @@
 	--gnome-tabbar-tab-active-hover-background: color-mix(in srgb, currentColor 13%, var(--gnome-tabbar-background));
 	--gnome-tabbar-tab-needs-attetion: var(--gnome-palette-blue-2);
 
-	--gnome-tabbar-identity-color-blue: var(--gnome-accent);
+	--gnome-tabbar-identity-color-blue: #0461be;
 	--gnome-tabbar-identity-color-turquoise: #00c79a;
 	--gnome-tabbar-identity-color-green: var(--gnome-palette-green-5);
 	--gnome-tabbar-identity-color-yellow: #ae7b03;