revert: undo unintended changes from previous commit

Author: R1shabh-Gupta

packages/block-library/src/navigation/style.scss

@@ -160,7 +160,7 @@ $navigation-icon-size: 24px;
 		background-color: inherit;
 		color: inherit;
 		position: absolute;
-		z-index: 2000;
+		z-index: 2;
 		display: flex;
 		flex-direction: column;
 		align-items: normal;