Icons: add xs icon size as a variable to reuse in components. See #77868

Author: Stefanie Hein

src/scss/themes/fylr/_variables.scss

@@ -331,6 +331,7 @@ $component-selected-border-color: var(--brand-color, #{$primary}) !default;
 
 // * Icons
 // * ==========================================
+$icon-font-size-xs: 	9px !default;
 $icon-font-size: 		$font-size-base !default;
 $icon-font-size-lg: 	20px !default;
 $icon-font-size-xl: 	30px !default;

src/scss/themes/fylr/mixins/_icons.scss

@@ -12,7 +12,7 @@
 
 @mixin icon-close-xs() {
 	.svg-close {
-		width: 9px;
-		height: 9px;
+		width: $icon-font-size-xs;
+		height: $icon-font-size-xs;
 	}
 }