Don't register unused RCTTimingCls in RN iOS (#57657)

Summary:

Changelog: [INTERNAL]

RCTTiming is NOT used in the RN new architecture: #57081

And will be deleted in: #57037

This change removes it from the binary

Differential Revision: D113474826

Author: christophpurrer

packages/react-native/React/CoreModules/CoreModulesPlugins.h

@@ -49,7 +49,9 @@ Class RCTPlatformCls(void) __attribute__((used));
 Class RCTRedBoxCls(void) __attribute__((used));
 Class RCTSourceCodeCls(void) __attribute__((used));
 Class RCTStatusBarManagerCls(void) __attribute__((used));
+#ifndef RCT_REMOVE_LEGACY_ARCH
 Class RCTTimingCls(void) __attribute__((used));
+#endif
 Class RCTWebSocketModuleCls(void) __attribute__((used));
 Class RCTBlobManagerCls(void) __attribute__((used));
 

packages/react-native/React/CoreModules/CoreModulesPlugins.mm

@@ -100,10 +100,6 @@ Class RCTCoreModulesClassProvider(const char *name)
     return RCTStatusBarManagerCls();
   }
 
-  if (name == "Timing"sv) {
-    return RCTTimingCls();
-  }
-
   if (name == "WebSocketModule"sv) {
     return RCTWebSocketModuleCls();
   }

packages/react-native/React/CoreModules/RCTTiming.mm

@@ -428,8 +428,3 @@ - (void)createTimerForNextFrame:(nonnull NSNumber *)callbackID
 }
 
 @end
-
-Class RCTTimingCls(void)
-{
-  return RCTTiming.class;
-}