feat: Add null check for hostname in Database.py

A null check for the "hostname" field has been added in the Database.py file. This ensures that instances without a hostname are skipped during processing, improving the reliability of the code.

src/common/db/Database.py

@@ -3106,6 +3106,9 @@ class Database:
             session.query(Instances).filter(Instances.method == method).delete()
 
             for instance in instances:
+                if instance.get("hostname") is None:
+                    continue
+
                 to_put.append(
                     Instances(
                         hostname=instance["hostname"],