Combine Cases uses the wrong capacity number for PV

[brtietz]

Describe the bug

When adding a PV case to the generic system's "combine cases" function, the function adds a dc system capacity to an AC system capacity number.

To Reproduce

Steps to reproduce the behavior:

1. Open multiple PV cases
2. Open a generic system case and choose the combine cases option
3. The (AC) combined capacity will be the sum of the DC capacity of the systems

Attached file demonstrates the issue:
combine_cases_ac_vs_dc_issue.zip

Expected behavior

Combine cases should use AC capacity numbers for all incoming systems.

Operating System and Version

• Version 2023.12.17, maybe others.