Do not set global validate_args

[mctigger]

tensordict/tensordict/nn/distributions/continuous.py

Line 25 in 02ff686

D.Distribution.set_default_validate_args(False)

Is there a reason for this line? I think it should be removed. validate_args is set to False when python is run in optimized mode (python -O) and True. The default should not be changed since errors may not be caught while developing.

#872