Fix debug loglevel

[huchenlei]

process_has_sdxl_refiner is a static method on Script. Calling it with self. prefix will cause issue when the method is decorated by

def timer_decorator(func):
    """Time the decorated function and output the result to debug logger."""
    if logger.level != logging.DEBUG:
        return func

    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        start_time = time.time()
        result = func(*args, **kwargs)
        end_time = time.time()
        duration = end_time - start_time
        # Only report function that are significant enough.
        if duration > 1e-3:
            logger.debug(f"{func.__name__} ran in: {duration} sec")
        return result

    return wrapper

in debug loglevel, as self.process_has_sdxl_refiner(p) will be interpreted as process_has_sdxl_refiner(self, p), but the function only accepts single param.

This PR fixes the issue by replacing self. with Script. in all callsites.

[huchenlei]

Sample stack trace:

*** Error running before_process_batch: D:\stable-diffusion-webui\extensions\sd-webui-controlnet\scripts\controlnet.py
    Traceback (most recent call last):
      File "D:\stable-diffusion-webui\modules\scripts.py", line 631, in before_process_batch
        script.before_process_batch(p, *script_args, **kwargs)
      File "D:\stable-diffusion-webui\extensions\sd-webui-controlnet\scripts\utils.py", line 90, in wrapper
        result = func(*args, **kwargs)
      File "D:\stable-diffusion-webui\extensions\sd-webui-controlnet\scripts\controlnet.py", line 986, in before_process_batch
        if self.process_has_sdxl_refiner(p):
      File "D:\stable-diffusion-webui\extensions\sd-webui-controlnet\scripts\utils.py", line 90, in wrapper
        result = func(*args, **kwargs)
    TypeError: Script.process_has_sdxl_refiner() takes 1 positional argument but 2 were given