Fix double metro banner in Bridgeless

Summary:
Following up facebook#43943, the metro loading banner is presented twice in Bridgeless mode.

This happens because both the RCTInstance and the RCTHost are listening to the Reload Command and issuing the instructions to refetch the JSBundle and to present the banner.

The RCTInstance should not concern itself with lifecycle events, owned by the RCTHost.

## Changelog:
[iOS][Fixed] - Avoid to show Metro Loading banner twice.

Reviewed By: cortinico

Differential Revision: D55870640

packages/react-native/ReactCommon/react/runtime/platform/ios/ReactCommon/RCTInstance.mm

@@ -31,7 +31,6 @@
 #import <React/RCTModuleData.h>
 #import <React/RCTPerformanceLogger.h>
 #import <React/RCTRedBox.h>
-#import <React/RCTReloadCommand.h>
 #import <React/RCTSurfacePresenter.h>
 #import <ReactCommon/RCTTurboModuleManager.h>
 #import <ReactCommon/RuntimeExecutor.h>
@@ -136,11 +135,6 @@ - (instancetype)initWithDelegate:(id<RCTInstanceDelegate>)delegate
                           name:@"RCTNotifyEventDispatcherObserversOfEvent_DEPRECATED"
                         object:nil];
 
-    [defaultCenter addObserver:self
-                      selector:@selector(didReceiveReloadCommand)
-                          name:RCTTriggerReloadCommandNotification
-                        object:nil];
-
     [self _start];
   }
   return self;
@@ -519,9 +513,4 @@ - (void)_handleJSError:(const JsErrorHandler::ParsedError &)error
                      isFatal:error.isFatal];
 }
 
-- (void)didReceiveReloadCommand
-{
-  [self _loadJSBundle:[_bridgeModuleDecorator.bundleManager bundleURL]];
-}
-
 @end