fix(isNumber): parse string parameter as number (allow string as parameter)

[sawa-ko]

This PR is due to the fact that this utility cannot accept a string as a value, so what has to be done is:

const numberString = '1';
isNumber(Number(numberString));

With this PR you will now be able to do the following:

const numberString = '1';
isNumber(numberString);

This helps for example, if you have an API and you receive a query parameter, this will come in string type, with this you can validate directly without the need to convert it to a number manually.