refactor: enhance multiply function to support variable arguments

[nborges-aws]

Enhanced Math Library's Multiply Function and Added Unit Tests

This PR introduces two main improvements:

1. Extends the multiply function to support variable number of arguments (varargs), making it more flexible and powerful
2. Adds comprehensive unit tests for both add and multiply functions to ensure reliability

The multiply function can now handle:

• Multiple arguments (more than 2 numbers)
• Single argument case
• Empty argument case (returns 1)

This change improves the utility of the Math library while maintaining backwards compatibility.