Remove redundant code

`get_charm_series` a line before is already running these lines

Author: cderici

juju/model.py

@@ -1793,11 +1793,6 @@ async def deploy(
                 if not application_name:
                     application_name = metadata['name']
                 series = series or await get_charm_series(charm_dir, self)
-                if not series:
-                    model_config = await self.get_config()
-                    default_series = model_config.get("default-series")
-                    if default_series:
-                        series = default_series.value
                 if not series:
                     raise JujuError(
                         "Couldn't determine series for charm at {}. "