Update mpas.ais4to20km and mpas.ais8to30km meshes to new versions

The updated mpas.ais4to20km mesh correctly handles merging bedmap2 for
Amundsen Sea Sector into the BedMachine geometry elsewhere.  The
previous version had an error in how that was done.

The updated mpas.ais8to30km mesh rolls back from an inadequately tested
8km mesh to the version that was used in ISMIP6-AIS-2300.

components/mpas-albany-landice/cime_config/buildnml

@@ -68,12 +68,12 @@ def buildnml(case, caseroot, compname):
         decomp_date += '150910'
         decomp_prefix += 'mpasli.graph.info.'
     elif glc_grid == 'mpas.ais8to30km':
-        grid_date += '20231222'
+        grid_date += '20221027'
         grid_prefix += 'ais_8to30km'
         decomp_date += '240507'
         decomp_prefix += 'mpasli.graph.info.'
     elif glc_grid == 'mpas.ais4to20km':
-        grid_date += '20230105'
+        grid_date += '20240708'
         grid_prefix += 'ais_4to20km'
         decomp_date += '240507'
         decomp_prefix += 'mpasli.graph.info.'