Fix error when calling enable_debug_mode twice

[arduinocc04]

When call enable_debug_mode twice, It makes error.

Traceback (most recent call last):
  File "/home/arduinocc04/Documents/GitHub/yfinance/test_yfinance.py", line 75, in <module>
    yf.enable_debug_mode()
  File "/home/arduinocc04/Documents/GitHub/yfinance/yfinance/utils.py", line 185, in enable_debug_mode
    setup_debug_formatting()
  File "/home/arduinocc04/Documents/GitHub/yfinance/yfinance/utils.py", line 172, in setup_debug_formatting
    if yf_logger.handlers is None or len(yf_logger.handlers) == 0:
       ^^^^^^^^^^^^^^^^^^
AttributeError: 'IndentLoggerAdapter' object has no attribute 'handlers'. Did you mean: 'hasHandlers'?

This error is so annoying when using jupyter and rerun code block.