Make userId optional in GetProgramsDto

Jellyfin.Api/Controllers/LiveTvController.cs

@@ -628,7 +628,7 @@ public class LiveTvController : BaseJellyfinApiController
     [Authorize(Policy = Policies.LiveTvAccess)]
     public async Task<ActionResult<QueryResult<BaseItemDto>>> GetPrograms([FromBody] GetProgramsDto body)
     {
-        var user = body.UserId.IsEmpty() ? null : _userManager.GetUserById(body.UserId);
+        var user = body.UserId.IsNullOrEmpty() ? null : _userManager.GetUserById(body.UserId.Value);
 
         var query = new InternalItemsQuery(user)
         {

Jellyfin.Api/Models/LiveTvDtos/GetProgramsDto.cs

@@ -22,7 +22,7 @@ public class GetProgramsDto
     /// <summary>
     /// Gets or sets optional. Filter by user id.
     /// </summary>
-    public Guid UserId { get; set; }
+    public Guid? UserId { get; set; }
 
     /// <summary>
     /// Gets or sets the minimum premiere start date.