Add NumPy .average() method documentation

[dancikmad]

• New Term entry to close issue [Term Entry] Python Numpy - math methods: .average() #6707

Description

• Adding a new term entry for Python - NumPy math methods .average()

• Add comprehensive documentation for numpy.average() function

• Include syntax, parameters, and return value descriptions

• Provide practical examples for educational and financial use cases

• Add multi-dimensional array processing example with axis specification

• Include interactive codebyte example for hands-on learning

• Add FAQ section covering common questions and edge cases

• Document weighted average functionality and comparison with numpy.mean()

• Cover complex number support and NaN handling behavior

Issue Solved

• Closing the issue [Term Entry] Python Numpy - math methods: .average() #6707

Type of Change

• Adding a new entry
• Updating the documentation

Checklist

• All writings are my own.
• My entry follows the Codecademy Docs style guide.
• My changes generate no new warnings.
• I have performed a self-review of my own writing and code.
• I have checked my entry and corrected any misspellings.
• I have made corresponding changes to the documentation if needed.
• I have confirmed my changes are not being pushed from my forked main branch.
• I have confirmed that I'm pushing from a new branch named after the changes I'm making.
• I have linked any issues that are relevant to this PR in the Issues Solved section.

[mamtawardhani]

Thank you for contributing to Codecademy Docs @dancikmad 😄

The entry looks good for a second round of review! 🚀