Update Node.js guide on retrieving float values

[matea16]

Update the current Node.js quick start guide on how to process results and retrieve float values and list of float values.
Example:

const floatProp = resultSingle.records[0].get('floatProp');
const floatValue = floatProp !== null && floatProp !== undefined ? Number(floatProp) : null;
console.log('Float value:', floatValue);

and for the lists:

const floatList = resultList.records[0].get('floatList') || [];
const floatValues = floatList.map(value => Number(value));
console.log('List of float values:', floatValues);