fix aerosols in forecast-only mode

[bbakernoaa]

Description

Aerosols in forecast-only mode would not generate an experiment or an xml file using the ATMA application

Type of change

• Bug fix (fixes something broken)

Change characteristics

• Is this a breaking change (a change in existing functionality)? NO
• Does this change require a documentation update? NO

How has this been tested?

• Forecast-only on Hera

Checklist

• Any dependent changes have been merged and published
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• New and existing tests pass with my changes
• I have made corresponding changes to the documentation if necessary

[aerorahul]

@bbakernoaa Just an FYI. #2757 added some similar changes as in this PR.

[bbakernoaa]

@aerorahul closing this as it duplicates with your latest one #2752