v12: Update to GEOS_OceanGridComp v3.9.0, mom6 geos/v3.8

[mathomp4]

This PR updates GEOS_OceanGridComp to v3.9.0. This has multiple fixes in the Ocean Grid Comp from @afahadabdullah, @sinakhani, @zhaobin74 and @adarmenov:

• v3: Magnitude of the surface stress passing into the MOM6 by @sinakhani in v3: Magnitude of the surface stress passing into the MOM6 GEOS_OceanGridComp#115
• v3: Set MEKE_POSITIVE to True by @mathomp4 in v3: Set MEKE_POSITIVE to True GEOS_OceanGridComp#114
• v3: mit C180 LLC270 config by @afahadabdullah in v3: mit C180 LLC270 config GEOS_OceanGridComp#97
• v3 improve JRA55-DO runoff distribution and add Ice calving flux by @zhaobin74 in v3 improve JRA55-DO runoff distribution and add Ice calving flux  GEOS_OceanGridComp#107

This also updates to use mom6 geos/v3.8 which has MOM6 as of 2026-Mar-03

This is zero-diff for the dataocean, but non-zero-diff for Coupled MOM6 runs.