chore: add more defensive checks for moduleConfig

Author: bevzzz

src/main/java/io/weaviate/client6/v1/api/collections/CollectionConfig.java

@@ -289,7 +289,7 @@ public CollectionConfig read(JsonReader in) throws IOException {
 
           // Separate modules into reranker- and generative- modules.
           var rerankerModules = new JsonArray();
-          if (jsonObject.has("moduleConfig")) {
+          if (jsonObject.has("moduleConfig") && jsonObject.get("moduleConfig").isJsonObject()) {
             var moduleConfig = jsonObject.remove("moduleConfig").getAsJsonObject();
 
             moduleConfig.entrySet().stream()

src/test/java/io/weaviate/client6/v1/internal/json/JSONTest.java

@@ -400,7 +400,7 @@ public void test_ReferenceAddManyResponse_CustomDeserializer() {
             "result": { "status": "SUCCESS", "errors": {} }
           },
           {
-            "result": { "status": "FAILED", "errors": jsonObject.has("properties") && {
+            "result": { "status": "FAILED", "errors": {
               "error": [ "oops" ]
             }}
           }