remove rubik font for headings (#7332)

texty/theme.json

@@ -539,7 +539,6 @@
 			},
 			"heading": {
 				"typography": {
-					"fontFamily": "var(--wp--preset--font-family--rubik)",
 					"fontStyle": "normal",
 					"fontWeight": "500",
 					"lineHeight": "1"