Optimize boolean indexing in CircularResistiveWall

This merge request includes minor optimizations for the LongitudinalWakeFunction and TransverseWakeFunction:

1. Removed "if np.any(idx2):"
   • In the LongitudinalWakeFunction, the condition if np.any(idx2): has been removed. The subsequent assignment wl[idx2] = 3 * factor / 2 inherently affects only where idx2 is True, making the conditional check redundant.
2. Removed "np.logical_not", "np.logical_or" and reduced redundant boolean indexing
   • np.logical_not, np.logical_or and redundant indexing have been removed, streamlining the indexing process and slightly improving code efficiency.