Update IsogonalOctagon to use xz basis and update tests

[ybadr16]

Description

Switched the zx basis for IsogonalOctagon to xz by following a similar strategy done to CylindricalSectors in #3018, updated the corresponding unit test so the second parameter matches the changes.

Fixes #3019

Checklist

• [ ✅] I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• [✅] I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• [✅] I have added tests that prove my fix is effective or that my feature works (if applicable)

[paulromano]

Thanks @ybadr16!