spec(overlay): remove css-variable related expectations

Author: simeonoff

projects/igniteui-angular/core/src/services/overlay/overlay.spec.ts

@@ -3222,9 +3222,6 @@ describe('igxOverlay', () => {
 
             expect(wrapperElement).toBeDefined();
             const styles = css(wrapperElement);
-            expect(styles.findIndex(
-                (e) => e.includes('--background-color: var(--ig-overlay-background-color, hsl(from var(--ig-gray-500) h s l/0.54));')))
-                .toBeGreaterThan(-1);
             expect(styles.findIndex(
                 (e) => e.includes('background: var(--background-color);')))
                 .toBeGreaterThan(-1);
@@ -3249,7 +3246,6 @@ describe('igxOverlay', () => {
                 .parentElement.getElementsByClassName(CLASS_OVERLAY_WRAPPER_MODAL)[0] as HTMLElement;
             expect(wrapperElement).toBeDefined();
             const styles = css(wrapperElement);
-            expect(styles.findIndex((e) => e.includes('--background-color: var(--ig-overlay-background-color, hsl(from var(--ig-gray-500) h s l/0.54));'))).toBeGreaterThan(-1);
             expect(styles.findIndex((e) => e.includes('background: var(--background-color);'))).toBeGreaterThan(-1);
 
             fixture.componentInstance.overlay.detachAll();