revert hashicorp#28494 wait SDK to support nullable values to support removing

the expiration_date by an update

Author: wuxu92

internal/services/keyvault/key_vault_secret_resource.go

@@ -101,16 +101,6 @@ func resourceKeyVaultSecret() *pluginsdk.Resource {
 
 			"tags": tags.SchemaWithMax(15),
 		},
-
-		CustomizeDiff: pluginsdk.CustomDiffWithAll(
-			pluginsdk.ForceNewIfChange("expiration_date", func(ctx context.Context, oldVal, newVal interface{}, meta interface{}) bool {
-				// if change from non-nil to nil, we need to force new
-				if oldVal != nil && oldVal.(string) != "" {
-					return newVal == nil || newVal.(string) == ""
-				}
-				return false
-			}),
-		),
 	}
 }
 

website/docs/r/key_vault_secret.html.markdown

@@ -87,7 +87,7 @@ The following arguments are supported:
 
 * `not_before_date` - (Optional) Key not usable before the provided UTC datetime (Y-m-d'T'H:M:S'Z').
 
-* `expiration_date` - (Optional) Expiration UTC datetime (Y-m-d'T'H:M:S'Z'). Removing this forces a new resource to be created.
+* `expiration_date` - (Optional) Expiration UTC datetime (Y-m-d'T'H:M:S'Z').
 
 ## Attributes Reference