fix: add missing vector_similarity_support in InferenceFeatures (elastic#138644)

(cherry picked from commit fe1bf19)

Author: mromaios

docs/changelog/138644.yaml

@@ -0,0 +1,5 @@
+pr: 138644
+summary: "Fix: add missing `vector_similarity_support` in InferenceFeatures"
+area: Search
+type: bug
+issues: []

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/InferenceFeatures.java

@@ -40,6 +40,9 @@ public class InferenceFeatures implements FeatureSpecification {
     private static final NodeFeature SEMANTIC_TEXT_HIGHLIGHTER_DISKBBQ_SIMILARITY_SUPPORT = new NodeFeature(
         "semantic_text.highlighter.bbq_and_similarity_support"
     );
+    private static final NodeFeature SEMANTIC_TEXT_HIGHLIGHTER_VECTOR_SIMILARITY_SUPPORT = new NodeFeature(
+        "semantic_text.highlighter.vector_similarity_support"
+    );
     private static final NodeFeature TEST_RERANKING_SERVICE_PARSE_TEXT_AS_SCORE = new NodeFeature(
         "test_reranking_service.parse_text_as_score"
     );
@@ -97,6 +100,7 @@ public Set<NodeFeature> getTestFeatures() {
                 SEMANTIC_TEXT_SPARSE_VECTOR_INDEX_OPTIONS,
                 SEMANTIC_TEXT_FIELDS_CHUNKS_FORMAT,
                 SEMANTIC_TEXT_HIGHLIGHTER_DISKBBQ_SIMILARITY_SUPPORT,
+                SEMANTIC_TEXT_HIGHLIGHTER_VECTOR_SIMILARITY_SUPPORT,
                 SemanticQueryBuilder.SEMANTIC_QUERY_MULTIPLE_INFERENCE_IDS,
                 SemanticQueryBuilder.SEMANTIC_QUERY_FILTER_FIELD_CAPS_FIX,
                 InterceptedInferenceQueryBuilder.NEW_SEMANTIC_QUERY_INTERCEPTORS,