feat: allow overAll aggregation with only the GroupBy argument

Author: bevzzz

src/main/java/io/weaviate/client6/v1/api/collections/aggregate/AbstractAggregateClient.java

@@ -60,6 +60,22 @@ public ResponseT overAll(Function<Aggregation.Builder, ObjectBuilder<Aggregation
     return performRequest(Aggregation.of(fn));
   }
 
+  /**
+   * Aggregate metrics over all objects in this collection.
+   *
+   * @param groupBy GroupBy clause.
+   * @return Grouped aggregation result.
+   *
+   * @throws WeaviateApiException in case the server returned with an
+   *                              error status code.
+   *
+   * @see GroupBy
+   * @see AggregateResponseGrouped
+   */
+  public GroupedResponseT overAll(GroupBy groupBy) {
+    return performRequest(Aggregation.of(), groupBy);
+  }
+
   /**
    * Aggregate metrics over all objects in this collection.
    *

src/main/java/io/weaviate/client6/v1/api/collections/aggregate/Aggregation.java

@@ -14,6 +14,10 @@ public record Aggregation(
     boolean includeTotalCount,
     List<PropertyAggregation> returnMetrics) {
 
+  public static Aggregation of() {
+    return of(AggregateObjectFilter.NONE, ObjectBuilder.identity());
+  }
+
   public static Aggregation of(Function<Builder, ObjectBuilder<Aggregation>> fn) {
     return of(AggregateObjectFilter.NONE, fn);
   }