Embeddings tweaks (#16864)

* make semantic search optional

* config

* frontend metrics

* docs

* tweak

* fixes

* also check genai cameras for embeddings context

web/src/pages/System.tsx

@@ -28,7 +28,11 @@ function System() {
   const metrics = useMemo(() => {
     const metrics = [...allMetrics];
 
-    if (!config?.semantic_search.enabled) {
+    if (
+      !config?.semantic_search.enabled &&
+      !config?.lpr.enabled &&
+      !config?.face_recognition.enabled
+    ) {
       const index = metrics.indexOf("features");
       metrics.splice(index, 1);
     }