fix(ui): avoid invalid requests after logoff

ui/src/subsonic/index.js

@@ -2,10 +2,17 @@ import { baseUrl } from '../utils'
 import { httpClient } from '../dataProvider'
 
 const url = (command, id, options) => {
+  const username = localStorage.getItem('username')
+  const token = localStorage.getItem('subsonic-token')
+  const salt = localStorage.getItem('subsonic-salt')
+  if (!username || !token || !salt) {
+    return ''
+  }
+
   const params = new URLSearchParams()
-  params.append('u', localStorage.getItem('username'))
+  params.append('u', username)
-  params.append('t', localStorage.getItem('subsonic-token'))
+  params.append('t', token)
-  params.append('s', localStorage.getItem('subsonic-salt'))
+  params.append('s', salt)
   params.append('f', 'json')
   params.append('v', '1.8.0')
   params.append('c', 'NavidromeUI')