Fix linting issue for agent config

Author: ozgen

gvm/protocols/gmp/requests/next/_agents.py

@@ -7,14 +7,14 @@
 from gvm.errors import RequiredArgument
 from gvm.protocols.core import Request
 from gvm.protocols.gmp.requests._entity_id import EntityID
-from gvm.utils import SupportsStr, to_bool
+from gvm.utils import to_bool
 from gvm.xml import XmlCommand
 
 
 class Agents:
 
     @staticmethod
-    def _add_element(element, name: str, value: Optional[SupportsStr]) -> None:
+    def _add_element(element, name: str, value: Any) -> None:
         """
         Helper to add a sub-element with a value if the value is not None.