fix: changing the logic for number of bands as the current one returns nil on iOS

[SaiChand-Headout]

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[CLAassistant]

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[SaiChand-Headout]

@davidliu , currently when you set the bands number in RN side, it's not being reflected as expected, when debugging found this piece of code, where the integer is being typecasted to string which is throwing nil. This is a small fix for that.

These were my values in RN side while calling the hook
const magnitudes = useMultibandTrackVolume(microphoneTrack?.audioTrack, {
bands: 20,
maxFrequency: 1000,
minFrequency: 0,
updateInterval: 100,
});

[davidliu]

Thanks for the PR!