Update theme.json (#7413)

Add fluid typography support.

meraki/theme.json

@@ -70,6 +70,9 @@
 			}
 		},
 		"typography": {
+			"customFontSize": true,
+			"dropCap": true,
+			"fluid": true,
 			"fontSizes": [
 				{
 					"name": "Tiny",