### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Problem Description

We need to load a custom error page when the certificate is invalid but without "isMainFrame" property we don't know when to load the custom error page using webContents.loadURL()

### Proposed Solution

webContents.on("certificate-error", ((event, url, error, certificate, callback, isMainFrame)

### Alternatives Considered

Not sure

### Additional Information

Not sure
shell/browser/api/electron_api_app.cc
&App::IsAccessibilitySupportEnabled)
      .SetMethod("setAccessibilitySupportEnabled",
                 &App::SetAccessibilitySupportEnabled)
      .SetMethod("disableHardwareAcceleration",
                 &App::DisableHardwareAcceleration)
      .SetMethod("disableDomainBlockingFor3DAPIs",
                 &App::DisableDomainBlockingFor3DAPIs)
      .SetMethod("getFileIcon", &App::GetFileIcon)
      .SetMethod("getAppMetrics", &App::GetAppMetrics)
      .SetMethod("getGPUFeatureStatus", &App::GetGPUFeatureStatus)
      .SetMethod("getGPUInfo", &App::GetGPUInfo)
#if defined(MAS_BUILD)
      .SetMethod("startAccessingSecurityScopedResource",
                 &App::StartAccessingSecurityScopedResource)
#endif
#if defined(OS_MAC)
      .SetProperty("dock", &App::GetDockAPI)
      .SetProperty("runningUnderRosettaTranslation",
                   &App::IsRunningUnderRosettaTranslation)
#endif
#if defined(OS_MAC) || defined(OS_WIN)
      .SetProperty("runningUnderARM64Translation",
                   &App::IsRunningUnderARM64Translation)
#endif
      .SetProperty("userAgentFallback", &App::GetUserAgentFallback,
                   &App::SetUserAgentFallback)
      .SetMethod("configureHostResolver", &ConfigureHostResolver)
      .SetMethod("enableSandbox", &App::EnableSandbox);
}
const char* App::GetTypeName() {