fix(specs): body is not required in multiple batch request (generated)

algolia/api-clients-automation#3454

Co-authored-by: algolia-bot <accounts+algolia-api-client-bot@algolia.com>
Co-authored-by: Kai Welke <kai.welke@algolia.com>

client/src/commonMain/kotlin/com/algolia/client/model/search/MultipleBatchRequest.kt

@@ -8,17 +8,17 @@ import kotlinx.serialization.json.*
  * MultipleBatchRequest
  *
  * @param action
- * @param body Operation arguments (varies with specified `action`).
  * @param indexName Index name (case-sensitive).
+ * @param body Operation arguments (varies with specified `action`).
  */
 @Serializable
 public data class MultipleBatchRequest(
 
   @SerialName(value = "action") val action: Action,
 
-  /** Operation arguments (varies with specified `action`). */
-  @SerialName(value = "body") val body: JsonObject,
-
   /** Index name (case-sensitive). */
   @SerialName(value = "indexName") val indexName: String,
+
+  /** Operation arguments (varies with specified `action`). */
+  @SerialName(value = "body") val body: JsonObject? = null,
 )