Fix server queue saving/restoring on Navidrome and OpenSubsonic (#1828)

* fix server queue saving

* fix error when attempting to restore empty queue

* queue items optional

* make playQueueByIndex optional

* fix incorrect error message

src/shared/api/navidrome/navidrome-types.ts

@@ -709,7 +709,7 @@ const queue = z.object({
     createdAt: z.string(),
     current: z.number(),
     id: z.string(),
-    items: z.array(song),
+    items: z.array(song).optional(),
     position: z.number(),
     updatedAt: z.string(),
     userId: z.string(),

src/shared/api/subsonic/subsonic-types.ts

@@ -667,14 +667,16 @@ const playQueue = z.object({
 });
 
 const playQueueByIndex = z.object({
-    playQueueByIndex: z.object({
-        changed: z.string(),
-        changedBy: z.string(),
-        currentIndex: z.number().optional(),
-        entry: song.array().optional(),
-        position: z.number().optional(),
-        username: z.string(),
-    }),
+    playQueueByIndex: z
+        .object({
+            changed: z.string(),
+            changedBy: z.string(),
+            currentIndex: z.number().optional(),
+            entry: song.array().optional(),
+            position: z.number().optional(),
+            username: z.string(),
+        })
+        .optional(),
 });
 
 const internetRadioStation = z.object({