Fix infinite rerendering bug when plugins array is provided

[dohyun-ko]

      <WavesurferPlayer
        height={100}
        waveColor={waveColor}
        url={audioUrls[urlIndex]}
        onReady={(ws) => setWavesurfer(ws)}
        onPlay={() => setIsPlaying(true)}
        onPause={() => setIsPlaying(false)}
        plugins={[]}
      />

When plugins array is provided like above (whether empty or not), useEffect in useWavesurferInstance causes infinite rerendering.

Fixed this bug by serializing the options instead of flattening them.