Fix memory unsetting on Gaea

[DavidHuber-NOAA]

Description

Memory requests are not valid on Gaea, so the variable must be unset when running the setup scripts there. This fixes memory unsetting when variables like memory_gdas are set in config.resources.

Resolves #3322

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
• Does this change require an update to any of the following submodules? NO

How has this been tested?

C48_S2SW on Gaea C6

Checklist

• 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
• This change is covered by an existing CI test or a new one has been added

[KateFriedman-NOAA]

Looks good and fixes the issue. Thanks @DavidHuber-NOAA !

[aerorahul]

thanks for the quick fix @DavidHuber-NOAA