TypeError when setting ExceptionDictTransformer's constructor arguments locals_max_string and locals_max_length to None

[Sh4pe]

As of version 24.3.0 (see #627), ExceptionDictTransformer interprets the constructor arguments locals_max_string and locals_max_length as type int | None where None supposedly disables abbreviation or truncation. However, if you set one of those to None, you get a TypeError:

TypeError: '<' not supported between instances of 'NoneType' and 'int'

This is because of the following snippet:

structlog/src/structlog/tracebacks.py

Lines 385 to 390 in 51641b7

	if locals_max_length < 0:
	msg = f'"locals_max_length" must be >= 0: {locals_max_length}'
	raise ValueError(msg)
	if locals_max_string < 0:
	msg = f'"locals_max_string" must be >= 0: {locals_max_string}'
	raise ValueError(msg)

It should contain logic that handles the None case.