Cover: background-attachment fixed iOS bug handling to properly work …

…with iOS 13 (#40087)

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

@@ -18,7 +18,7 @@
 		// Mobile Safari does not support fixed background attachment properly.
 		// See also https://stackoverflow.com/questions/24154666/background-size-cover-not-working-on-ios
 		// Chrome on Android does not appear to support the attachment at all: https://issuetracker.google.com/issues/36908439
-		@supports (-webkit-overflow-scrolling: touch) {
+		@supports (-webkit-touch-callout: inherit) {
 			background-attachment: scroll;
 		}