Actions: Remove --no-index from Wheel test build command

[simmsa]

This is a fix for:

https://github.com/MHKiT-Software/MHKiT-Python/actions/runs/18594536347/job/53017269068#step:6:14

Run pip install 'mhkit[all]' --no-index --find-links dist/
Looking in links: dist/
Processing ./dist/mhkit-1.0.1-py3-none-any.whl
INFO: pip is looking at multiple versions of mhkit[all] to determine which version is compatible with other requirements. This could take a while.
ERROR: Could not find a version that satisfies the requirement numpy>=2.0.0 (from mhkit[all]) (from versions: none)
ERROR: No matching distribution found for numpy>=2.0.0
Error: Process completed with exit code 1.

This fix removes --no-index which caused pip to only use local packages, which causes the above failure for any/all external packages/modules.

[simmsa]

@akeeste, this is good to go. This should solve the above test failure. This adds a new action: https://github.com/MHKiT-Software/MHKiT-Python/actions/runs/18597697846/job/53028120592 to verify the wheel build in develop. We may not need to keep this, but I wanted to verify that the pip command changes worked before we run the pypi.yml jobs.

[akeeste]

This looks good and will prevent future build failures from getting on pypi. The relevant tests are passing.