[Azure Mgmt Generator] Support `builtInResourceOperation` decorator in our resource detection logic

[ArcturusZhang]

The NspConfigurations related resource operations use this decorator.

like this:

/**
 * Network security perimeter (NSP) configuration resource
 */
@parentResource(BatchAccount)
model NetworkSecurityPerimeterConfiguration
  is Azure.ResourceManager.NspConfiguration;

alias NspConfigurationOperations = Azure.ResourceManager.NspConfigurations<NetworkSecurityPerimeterConfiguration>;

@armResourceOperations
@tag("NetworkSecurityPerimeter")
interface NetworkSecurityPerimeterConfigurations {
  /**
   * Gets information about the specified NSP configuration.
   */
  getConfiguration is NspConfigurationOperations.Read<
    ParentResource = BatchAccount,
    Resource = NetworkSecurityPerimeterConfiguration,
    Response = CommonTypes.NetworkSecurityPerimeterConfiguration,
    Error = CloudError
  >;

  /**
   * Lists all of the NSP configurations in the specified account.
   */
  @list
  listConfigurations is NspConfigurationOperations.ListByParent<
    ParentResource = BatchAccount,
    Resource = NetworkSecurityPerimeterConfiguration,
    Response = CommonTypes.NetworkSecurityPerimeterConfigurationListResult,
    Error = CloudError
  >;

  /**
   * Reconciles the specified NSP configuration.
   */
  @post
  @action("reconcile")
  reconcileConfiguration is NspConfigurationOperations.Read<
    ParentResource = BatchAccount,
    Resource = NetworkSecurityPerimeterConfiguration,
    Response = ArmAcceptedLroResponse
  >;
}