Remove default value for featureProperties in GraphSage

The default value was invalid and just lead to confusing docs.

Author: FlorentinD

algo/src/main/java/org/neo4j/gds/embeddings/graphsage/algo/GraphSageTrainConfig.java

@@ -62,6 +62,9 @@ public interface GraphSageTrainConfig extends
 
     long serialVersionUID = 0x42L;
 
+    @Override
+    List<String> featureProperties();
+
     @Override
     @Value.Default
     default int embeddingDimension() {

algo/src/test/java/org/neo4j/gds/embeddings/graphsage/algo/GraphSageConfigTest.java

@@ -72,6 +72,15 @@ void specifyBatchesPerIteration(double samplingRatio, long nodeCount, int expect
     @Test
     void shouldThrowIfNoPropertiesProvided() {
         var mapWrapper = CypherMapWrapper.create(Map.of("modelName", "foo"));
+        var expectedMessage = "No value specified for the mandatory configuration parameter `featureProperties`";
+        assertThatThrownBy(() -> GraphSageTrainConfig.of("", mapWrapper))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessage(expectedMessage);
+    }
+
+    @Test
+    void shouldThrowIfEmptyPropertiesProvided() {
+        var mapWrapper = CypherMapWrapper.create(Map.of("modelName", "foo", "featureProperties", List.of()));
         var expectedMessage = "GraphSage requires at least one property.";
         assertThatThrownBy(() -> GraphSageTrainConfig.of("", mapWrapper))
             .isInstanceOf(IllegalArgumentException.class)

doc/modules/ROOT/partials/algorithms/common-configuration/common-train-configuration-entries.adoc

@@ -1,3 +1,3 @@
 | modelName                                                     | String       | n/a     | no       | The name of the model to train, must not exist in the Model Catalog.
-| featureProperties                                             | List of String | []      | yes      | The names of the node properties that should be used as input features. All property names must exist in the projected graph and be of type Float or List of Float.
+| featureProperties                                             | List of String | n/a      | no      | The names of the node properties that should be used as input features. All property names must exist in the projected graph and be of type Float or List of Float.
 include::partial$/algorithms/common-configuration/common-configuration-entries.adoc[]