Do not set eval() globals in ImageMath.unsafe_eval()

[radarhere]

Pillow/src/PIL/ImageMath.py

Line 310 in 087376d

out = builtins.eval(expression, {"__builtins": {"abs": abs}}, args)

The use of {"__builtins": {"abs": abs}} rather than {"__builtins__": {"abs": abs}} looks like a typo from #5923

However, if I abandon it entirely and just use None, nothing breaks, so I suggest that as the cleanest code.

https://docs.python.org/3/library/functions.html#eval

Overriding __builtins__ can be used to restrict or change the available names, but this is not a security mechanism: the executed code can still access all builtins.