BUG: Replace deprecated np.row_stack with np.vstack for NumPy 1.25+ compatibility

[samay2504]

Description

The np.row_stack function is an alias for np.vstack that was officially deprecated in NumPy 1.25. esda uses np.row_stack in multiple places:

• esda/crand.py
• esda/moran_local_mv.py

When tests are run using NumPy versions >= 1.25, DeprecationWarnings are thrown, contributing to noisy CI output.

To Reproduce

Run tests via pytest with a modern NumPy installation (e.g., 1.26 or 2.0+).
D:\Projects2.0\Gsoc\NumFocus\esda\esda\crand.py:560: DeprecationWarning: \row_stack` alias is deprecated. Use `np.vstack` directly.`

Expected behavior

The codebase should natively use np.vstack to suppress deprecation warnings and maintain future compatiblity when np.row_stack is permanently removed.