Frontogenesis function should be computed on pressure levels

[PeterHjortLauritzen]

What happened?

Walter Hannah (DOE) reported a bug in the computation of the frontogenesis function (computed in dp_coupling; dycore dependent) that was brough to our attention by @chihchen24. Code modification for cam_development provided by Walter Hannah and Jack Chen.

This needs to be fixed for all dynamical cores computing the frontogensis function. @kuanchihwang @JulioTBacmeister @mgduda @mbramberger @mijeong135

@PeterHjortLauritzen will do PR for SE (since we need it ASAP for CESM3)

Also: we need to make same changes in CAM-SIMA for SE and MPAS.

What are the steps to reproduce the bug?

Run any version of CAM7 or WACCM!

What CAM tag were you using?

any tag

What machine were you running CAM on?

CISL machine (e.g. cheyenne)

What compiler were you using?

Intel

Path to a case directory, if applicable

No response

Will you be addressing this bug yourself?

Yes, but I will need some help

Extra info

No response