Change immutabilityDurationDays minimum from 1 to 0

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Rui Zhan

specification/compute/resource-manager/Microsoft.Compute/Compute/ComputeDisk/models.tsp

@@ -1164,7 +1164,7 @@ model ImmutabilityPolicyData {
   /**
    * The immutability duration for the snapshot, in number of days.
    */
-  @minValue(1)
+  @minValue(0)
   immutabilityDurationDays: int32;
 
   /**

specification/compute/resource-manager/Microsoft.Compute/Compute/stable/2026-03-02/DiskRP.json

@@ -4267,7 +4267,7 @@
           "type": "integer",
           "format": "int32",
           "description": "The immutability duration for the snapshot, in number of days.",
-          "minimum": 1
+          "minimum": 0
         },
         "type": {
           "$ref": "#/definitions/ImmutabilityPolicyType",