Merge branch 'gridded-seis-59' into 'main'

Adjusting transition GMMs to 2/3 NGA-West2 and 1/3 NGA-East

See merge request !122

stable-crust/grid/system-stable/gmm-tree.json

 [
-  { "id": "NGA_EAST_2023", "weight": 0.16665 },
-  { "id": "NGA_EAST_2023_ADJUSTED", "weight": 0.16665 },
-  { "id": "NGA_EAST_SEEDS_2023", "weight": 0.08335 },
-  { "id": "NGA_EAST_SEEDS_2023_ADJUSTED", "weight": 0.08335 },
-  { "id": "ASK_14_BASIN", "weight": 0.125 },
-  { "id": "BSSA_14_BASIN", "weight": 0.125 },
-  { "id": "CB_14_BASIN", "weight": 0.125 },
-  { "id": "CY_14_BASIN", "weight": 0.125 }  
+  { "id": "NGA_EAST_2023", "weight": 0.1111 },
+  { "id": "NGA_EAST_2023_ADJUSTED", "weight": 0.1111 },
+  { "id": "NGA_EAST_SEEDS_2023", "weight": 0.05555 },
+  { "id": "NGA_EAST_SEEDS_2023_ADJUSTED", "weight": 0.05555 },
+  { "id": "ASK_14_BASIN", "weight": 0.1667 },
+  { "id": "BSSA_14_BASIN", "weight": 0.1667 },
+  { "id": "CB_14_BASIN", "weight": 0.1667 },
+  { "id": "CY_14_BASIN", "weight": 0.1666 }  
 ]