WebUI: Set icon sizes attribute

Gives browsers more information to pick the best icon.
PR #15540.

src/webui/www/private/index.html

@@ -5,8 +5,8 @@
     <meta charset="UTF-8" />
     <meta http-equiv="X-UA-Compatible" content="IE=10" />
     <title>qBittorrent Web UI</title>
-    <link rel="icon" type="image/png" href="images/qbittorrent32.png" />
-    <link rel="icon" type="image/svg+xml" href="icons/qbittorrent-tray.svg" />
+    <link rel="icon" type="image/png" href="images/qbittorrent32.png" sizes="32x32" />
+    <link rel="icon" type="image/svg+xml" href="icons/qbittorrent-tray.svg" sizes="any" />
     <link rel="stylesheet" type="text/css" href="css/dynamicTable.css?v=${CACHEID}" />
     <link rel="stylesheet" type="text/css" href="css/style.css?v=${CACHEID}" />
     <!--<link rel="stylesheet" type="text/css" href="css/Content.css" />-->