Add minimum segment length threshold to energy VAD to prevent processing short segments

speechbrain/inference/VAD.py", line 641, in create_chunks
    x = x.unfold(1, chunk_size, chunk_stride)
RuntimeError: maximum size for tensor at dimension 1 is 159 but size is 160

Added minimum segment length threshold to energy VAD function to prevent processing of very short segments. This change avoids applying unfold to segments shorter than chunk_size.

The modification adds a new parameter min_segment_length (default: 0.1 seconds) to the energy_VAD function. This enhancement is particularly useful for applications dealing with spontaneous speech or noisy environments where many short segments might be detected.

No new dependencies are required for this change. No breaking changes. The new parameter has a default value that maintains backward compatibility.

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