Fix: Remove GB200 from list of Fabric Manager SKUs (#7402)

Author: abenn135

pkg/agent/datamodel/gpu_components.go

@@ -120,8 +120,6 @@ var FabricManagerGPUSizes = map[string]bool{
 	"standard_nd96is_h200_v5":   true,
 	"standard_nd96isr_h200_v5":  true,
 	"standard_nd96isrf_h200_v5": true,
-	// GB200 (Grace Blackwell)
-	"standard_nd128isr_ndr_gb200_v6": true,
 	// A100 oddballs.
 	"standard_nc24ads_a100_v4": false, // NCads_v4 will fail to start fabricmanager.
 	"standard_nc48ads_a100_v4": false,