Implement requiresMainQueueSetup in RCTDevSettings.mm

Summary: Changelog: [Fixed] Implement requiresMainQueueSetup in RCTDevSettings

Reviewed By: PeteTheHeat, RSNara

Differential Revision: D19944271

fbshipit-source-id: 5163a5de2aab6ec2bb130589191a2b66d1b30c18

React/CoreModules/RCTDevSettings.mm

@@ -67,6 +67,11 @@ void RCTDevSettingsSetEnabled(BOOL enabled) {
   return [self initWithDefaultValues:nil];
 }
 
++ (BOOL)requiresMainQueueSetup
+{
+  return NO;
+}
+
 - (instancetype)initWithDefaultValues:(NSDictionary *)defaultValues
 {
   if (self = [super init]) {