Forward host:didInitializeRuntime: callback to user delegate

RCTReactNativeFactory acts as RCTHost's delegate but did not implement
host:didInitializeRuntime:, causing the optional callback to never reach
the user's RCTReactNativeFactoryDelegate.

Add the missing forwarding method following the same pattern as
hostDidStart: so the runtime reference is properly delivered to the
user delegate.

Changelog:
[IOS] [FIXED] - Forward host:didInitializeRuntime: callback to user delegate in RCTReactNativeFactory

Author: zhongwuzw

packages/react-native/Libraries/AppDelegate/RCTReactNativeFactory.mm

@@ -212,6 +212,13 @@ - (void)hostDidStart:(RCTHost *)host
   }
 }
 
+- (void)host:(RCTHost *)host didInitializeRuntime:(facebook::jsi::Runtime &)runtime
+{
+  if ([_delegate respondsToSelector:@selector(host:didInitializeRuntime:)]) {
+    [_delegate host:host didInitializeRuntime:runtime];
+  }
+}
+
 - (NSArray<NSString *> *)unstableModulesRequiringMainQueueSetup
 {
 #if RN_DISABLE_OSS_PLUGIN_HEADER