[CODEMOD][pytorch] replace uses of np.ndarray with npt.NDArray (#3845)

Differential Revision: D64619891

Pull Request resolved: https://github.com/pytorch/audio/pull/3846

test/torchaudio_unittest/prototype/functional/dsp_utils.py

 import numpy as np
+import numpy.typing as npt
 
 
 def oscillator_bank(
@@ -43,8 +44,8 @@ def freq_ir(magnitudes):
 
 
 def exp_sigmoid(
-    input: np.ndarray, exponent: float = 10.0, max_value: float = 2.0, threshold: float = 1e-7
-) -> np.ndarray:
+    input: npt.NDArray, exponent: float = 10.0, max_value: float = 2.0, threshold: float = 1e-7
+) -> npt.NDArray:
     """Exponential Sigmoid pointwise nonlinearity (Numpy version).
     Implements the equation:
     ``max_value`` * sigmoid(``input``) ** (log(``exponent``)) + ``threshold``