Ability to change the strength of safety_checker

[suzukimain]

What does this PR do?

Fixes #9003

"""
About safety_Level.
`int` or `float` or one of the following
'WEAK',
'MEDIUM',
'NOMAL',
'STRONG',
'MAX'.
"""

#To see the filter strength.
pipe.filter_level() # 0.0 (default)

#--------------
#If you want to change the intensity.
pipe.safety_checker_level("STRONG")
pipe.filter_level() # 1.0

#--------------
# If numbers are used
pipe.safety_checker_level(3.0)
pipe.filter_level() # 3.0

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