Architecture indicator: hide the overlay when Fabric/TM are both disabled

Summary: Instead of showing a thin gray line, don't render anything if no new architecture project is active.

Reviewed By: ejanzer

Differential Revision: D17142557

fbshipit-source-id: 644a8e515c04f84336d80bea00d641c2bfa3be41

Libraries/ReactNative/ReactNativeArchitectureIndicator.js

@@ -32,6 +32,11 @@ function ReactNativeArchitectureIndicator(props: {|
       parts.push('TM');
     }
   }
+
+  if (parts.length === 0) {
+    return null;
+  }
+
   return (
     <View style={styles.container}>
       <Text style={styles.text}>{parts.join('+')}</Text>