Fix double bracket indexing bug on Hermes noise model

[atvasilopoulos]

Description

Double brackets were used to index a torch tensor in the hermes noise model, leading to a UserWarning when using it. Fixed this by changing it to proper indexing.

Details

The following warning was raised when using the hermes noise model (model.program_analog_weights()).

UserWarning: Using a non-tuple sequence for multidimensional indexing is deprecated and will be changed in pytorch 2.9; use x[tuple(seq)] instead of x[seq]. In pytorch 2.9 this will be interpreted as tensor index, x[torch.tensor(seq)], which will result either in an error or a different result (Triggered internally at /__w/pytorch/pytorch/torch/csrc/autograd/python_variable_indexing.cpp:349.)
  g_relative[[g_relative >= 0.0945]],

Found 5 instances where this indexing pattern was used in the class. Single bracket solves the issue.