Add checks for valid auth data before making API calls for media

OF DL.Core/Services/ApiService.cs

@@ -147,6 +147,12 @@ public class ApiService(IAuthService authService, IConfigService configService,
         return headers;
     }
 
+    private bool HasSignedRequestAuth()
+    {
+        Auth? currentAuth = authService.CurrentAuth;
+        return currentAuth is { UserId: not null, Cookie: not null, UserAgent: not null, XBc: not null };
+    }
+
 
     /// <summary>
     /// Retrieves user information from the API.
@@ -157,6 +163,11 @@ public class ApiService(IAuthService authService, IConfigService configService,
     {
         Log.Debug($"Calling GetUserInfo: {endpoint}");
 
+        if (!HasSignedRequestAuth())
+        {
+            return null;
+        }
+
         try
         {
             UserEntities.User user = new();
@@ -197,6 +208,11 @@ public class ApiService(IAuthService authService, IConfigService configService,
     /// <returns>A JSON object when available.</returns>
     public async Task<JObject?> GetUserInfoById(string endpoint)
     {
+        if (!HasSignedRequestAuth())
+        {
+            return null;
+        }
+
         try
         {
             HttpClient client = new();
@@ -272,6 +288,11 @@ public class ApiService(IAuthService authService, IConfigService configService,
     {
         Log.Debug("Calling GetLists");
 
+        if (!HasSignedRequestAuth())
+        {
+            return null;
+        }
+
         try
         {
             int offset = 0;
@@ -333,6 +354,11 @@ public class ApiService(IAuthService authService, IConfigService configService,
     {
         Log.Debug($"Calling GetListUsers - {endpoint}");
 
+        if (!HasSignedRequestAuth())
+        {
+            return null;
+        }
+
         try
         {
             int offset = 0;
@@ -393,6 +419,11 @@ public class ApiService(IAuthService authService, IConfigService configService,
     {
         Log.Debug($"Calling GetMedia - {username}");
 
+        if (!HasSignedRequestAuth())
+        {
+            return null;
+        }
+
         try
         {
             Dictionary<long, string> returnUrls = new();
@@ -2928,6 +2959,11 @@ public class ApiService(IAuthService authService, IConfigService configService,
     private async Task<Dictionary<string, long>?> GetAllSubscriptions(Dictionary<string, string> getParams,
         string endpoint, bool includeRestricted)
     {
+        if (!HasSignedRequestAuth())
+        {
+            return null;
+        }
+
         try
         {
             Dictionary<string, long> users = new();