[iOS] Bridge: Fixes HostTarget use after free when deallocated bridge

[zhongwuzw]

Summary:

Fixes #48805 .

Changelog:

[IOS] [FIXED] - Bridge: Fixes HostTarget use after free when deallocated bridge

Test Plan:

Test code:

  __weak RCTAlertManager *weakModule;
  @autoreleasepool {
    RCTAlertManager *module = [RCTAlertManager new];
    RCTBridge *bridge = [[RCTBridge alloc] initWithBundleURL:[self sourceURLForBridge:nil]
                                              moduleProvider:^{
      return @[ module ];
    }
                                               launchOptions:nil];
    weakModule = module;
    (void)bridge;
  }

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