Fix fallback issues with nodes destination in _barycentric_weights()

[erogluorhan]

Closes #1451

Overview

Fixes the fallback case in _barycentric_weights() that was pointed out in #1451.

Also adds a test case to test against a pair of mesh files for which UXarray's remap.bilinear(..., remap_to="nodes", ...) failed before.

PR Checklist

General

• An issue is linked created and linked
• Add appropriate labels
• Filled out Overview and Expected Usage (if applicable) sections

Testing

• Adequate tests are created if there is new functionality
• Tests cover all possible logical paths in your function
• Tests are not too basic (such as simply calling a function and nothing else)

Documentation

• Docstrings have been added to all new functions