Relax the requirement that lazy module cannot be initialized on the main thread

Summary:
[RN] Relax the requirement that lazy module cannot be initialized on the main thread
I tried to understand the D5364734 that intoduced this, and I am not sure, but belive that asserting here is too strict. If you have a module that you want to lazily initialize, and module does not demand the main queue, it should be just a warning if you run on the main queue, not necessarily an error.

Reviewed By: mmmulani

Differential Revision: D10429880

fbshipit-source-id: 018c211d45b98dd8c552bf0289fe517d05e56d47

Author: spredolac

Diff for: React/CxxBridge/RCTCxxBridge.mm

@@ -603,8 +603,6 @@ - (void)registerExtraModules
                                withDispatchGroup:(dispatch_group_t)dispatchGroup
                                 lazilyDiscovered:(BOOL)lazilyDiscovered
 {
-  RCTAssert(!(RCTIsMainQueue() && lazilyDiscovered), @"Lazy discovery can only happen off the Main Queue");
-
   // Set up moduleData for automatically-exported modules
   NSArray<RCTModuleData *> *moduleDataById = [self registerModulesForClasses:modules];