avoid OverflowError and LinAlgError; pyina to 0.2.9

[mmckerns]

Summary

• bump pyina to 0.2.9
• use np.square(r) and np.power(r, n) instead of r**2 and r**n to avoid OverflowError
• use mystic.math.rbf instead of scipy.interpolate.rbf for thin_plate when throws LinAlgError
• corrected docs in mystic.math.sample to match arg names

Checklist

Documentation and Tests

• Added relevant documentation that builds in sphinx without error.
• Artifacts produced with the main branch work as expected under this PR.