Remove didMountComponentsWithRootTag on the new arch (#2687)

## Description

Removes usage of `didMountComponentsWithRootTag` on the new
architecture. It was doing exactly the same thing as `flushOperations`
but was executed on a different thread, which could cause crashes.
Removing this method shouldn't change any behavior as `flushOperations`
is scheduled after every operation.

Closes
#2658
 
## Test plan

See
#2658

apple/RNGestureHandlerModule.mm

@@ -10,7 +10,6 @@
 #ifdef RCT_NEW_ARCH_ENABLED
 #import <React/RCTBridge+Private.h>
 #import <React/RCTBridge.h>
-#import <React/RCTSurfacePresenter.h>
 #import <React/RCTUtils.h>
 #import <ReactCommon/CallInvoker.h>
 #import <ReactCommon/RCTTurboModule.h>
@@ -34,7 +33,7 @@
 #endif // RCT_NEW_ARCH_ENABLED
 
 #ifdef RCT_NEW_ARCH_ENABLED
-@interface RNGestureHandlerModule () <RCTSurfacePresenterObserver, RNGestureHandlerStateManager>
+@interface RNGestureHandlerModule () <RNGestureHandlerStateManager>
 
 @end
 #else
@@ -68,9 +67,7 @@ - (void)invalidate
 
   _manager = nil;
 
-#ifdef RCT_NEW_ARCH_ENABLED
-  [self.bridge.surfacePresenter removeObserver:self];
-#else
+#ifndef RCT_NEW_ARCH_ENABLED
   [self.bridge.uiManager.observerCoordinator removeObserver:self];
 #endif // RCT_NEW_ARCH_ENABLED
 }
@@ -115,9 +112,7 @@ - (void)setBridge:(RCTBridge *)bridge
                                                 eventDispatcher:bridge.eventDispatcher];
   _operations = [NSMutableArray new];
 
-#ifdef RCT_NEW_ARCH_ENABLED
-  [bridge.surfacePresenter addObserver:self];
-#else
+#ifndef RCT_NEW_ARCH_ENABLED
   [bridge.uiManager.observerCoordinator addObserver:self];
 #endif // RCT_NEW_ARCH_ENABLED
 }
@@ -243,27 +238,7 @@ - (void)addOperationBlock:(GestureHandlerOperation)operation
   [_operations addObject:operation];
 }
 
-#pragma mark - RCTSurfacePresenterObserver
-
-#ifdef RCT_NEW_ARCH_ENABLED
-
-- (void)didMountComponentsWithRootTag:(NSInteger)rootTag
-{
-  RCTAssertMainQueue();
-
-  if (_operations.count == 0) {
-    return;
-  }
-
-  NSArray<GestureHandlerOperation> *operations = _operations;
-  _operations = [NSMutableArray new];
-
-  for (GestureHandlerOperation operation in operations) {
-    operation(self->_manager);
-  }
-}
-
-#else
+#ifndef RCT_NEW_ARCH_ENABLED
 
 #pragma mark - RCTUIManagerObserver