Refactor External volumes check

Author: r4victor

src/dstack/_internal/server/services/volumes.py

@@ -400,23 +400,19 @@ def _validate_volume_configuration(configuration: VolumeConfiguration):
         )
     if configuration.name is not None:
         validate_dstack_resource_name(configuration.name)
-    # External volumes (with volume_id) cannot have auto_cleanup_duration
+
     if configuration.volume_id is not None and configuration.auto_cleanup_duration is not None:
         if (
             isinstance(configuration.auto_cleanup_duration, int)
-            and configuration.auto_cleanup_duration >= 0
+            and configuration.auto_cleanup_duration > 0
+        ) or (
+            isinstance(configuration.auto_cleanup_duration, str)
+            and configuration.auto_cleanup_duration not in ("off", "-1")
         ):
             raise ServerClientError(
                 "External volumes (with volume_id) do not support auto_cleanup_duration. "
                 "Auto-cleanup only works for volumes created and managed by dstack."
             )
-        elif isinstance(
-            configuration.auto_cleanup_duration, str
-        ) and configuration.auto_cleanup_duration not in ("off", "-1"):
-            raise ServerClientError(
-                "External volumes (with volume_id) do not support auto_cleanup_duration. "
-                "Auto-cleanup only works for volumes created and managed by dstack."
-            )
 
 
 async def _delete_volume(session: AsyncSession, project: ProjectModel, volume_model: VolumeModel):