Fix double metro banner in Bridgeless (#43967)

Summary:
Pull Request resolved: #43967

Following up #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

fbshipit-source-id: addb67d3226f7d7db20736309172a42fc15f3aa3

Author: cipolleschi

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