Call RCTInitializing initialize on TurboModules

Summary:
After D28435078, TurboModules can conform to the RCTInitializing protocol, and implement the `-(void)initialize` method. This diff makes the TurboModule system execute the module's initialize method after the infra is done setting it up.

Changelog: [Internal]

Reviewed By: fkgozali

Differential Revision: D28435429

fbshipit-source-id: fe945d616b97ed89f48b914b064e518b122a7b7b

ReactCommon/react/nativemodule/core/platform/ios/RCTTurboModuleManager.mm

@@ -18,6 +18,7 @@
 #import <React/RCTBridge+Private.h>
 #import <React/RCTBridgeModule.h>
 #import <React/RCTCxxModule.h>
+#import <React/RCTInitializing.h>
 #import <React/RCTLog.h>
 #import <React/RCTModuleData.h>
 #import <React/RCTPerformanceLogger.h>
@@ -605,6 +606,13 @@ static Class getFallbackClassFromName(const char *name)
     [_bridge attachBridgeAPIsToTurboModule:module];
   }
 
+  /**
+   * If the TurboModule conforms to RCTInitializing, invoke its initialize method.
+   */
+  if ([module respondsToSelector:@selector(initialize)]) {
+    [(id<RCTInitializing>)module initialize];
+  }
+
   /**
    * Attach method queue to id<RCTTurboModule> object.
    * This is necessary because the id<RCTTurboModule> object can be eagerly created/initialized before the method