Minor fix on app node fields

Remove offline_minutes from AppNodeWithReports and update query condition for active app node filter

src/db/app.rs

@@ -231,7 +231,6 @@ pub struct AppNodeWithReports {
     pub avail_ports: u32,
     pub max_ports_per_app: u32,
     pub price: u64,
-    pub offline_minutes: u64,
     pub reports: Vec<Report>,
 }
 
@@ -269,6 +268,8 @@ impl AppNodeWithReports {
             filter_query += &format!("&& ip = '{}' ", filters.ip);
         }
 
+        filter_query += " && connected_at > disconnected_at ";
+
         if limit_one {
             filter_query += "limit 1";
         }