Show main and sub stream usage separately in Storage Metrics (#24015)

* backend

* frontend

* docs

* test

* report null instead of 0 for a stream with no cached bandwidth sample

web/src/views/system/StorageMetrics.tsx

@@ -1,6 +1,6 @@
 import { CombinedStorageGraph } from "@/components/graph/CombinedStorageGraph";
 import { StorageGraph } from "@/components/graph/StorageGraph";
-import { FrigateStats } from "@/types/stats";
+import { CameraStorage, FrigateStats } from "@/types/stats";
 import { useEffect, useMemo } from "react";
 import {
   Popover,
@@ -24,14 +24,6 @@ import { LuExternalLink } from "react-icons/lu";
 import { FaExclamationTriangle } from "react-icons/fa";
 import ActivityIndicator from "@/components/indicators/activity-indicator";
 
-type CameraStorage = {
-  [key: string]: {
-    bandwidth: number;
-    usage: number;
-    usage_percent: number;
-  };
-};
-
 type StorageMetricsProps = {
   setLastUpdated: (last: number) => void;
 };