Fix Federal Depreciation Calculation in Host Developer Send-to-Excel with Equations

[cpaulgilman]

Cell CashFlow!B398 incorrectly referred to $C$141 for federal custom depreciation allocation which caused divide by zero errors that propagated through workbook all the way to LCOE and NPV results.

This issue only affected Host Developer send-to-Excel with equations when 20-yr SL allocation (Inputs!C141) is set to zero.

Checked that all other FOM spreadsheets do not have this problem.

Fixes #1784

Type of change

Please delete options that are not relevant.

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update
• [ ] This change modifies variables in existing compute modules. Please see Checking for PySAM Incompatible API Changes.

Checklist:

If you have added a new compute module in a SSC pull request related to this one, be sure to check the Process Requirements.

• [X] My code follows the style guidelines of this project
• [X] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [X] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [X] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules
• [X] I have checked my code and corrected any misspellings