fix(BA-1167): Wrong custom image owner check logic (#4181)

Author: jopemachine

changes/4181.fix.md

@@ -0,0 +1 @@
+Fix wrong custom image owner check logic.

src/ai/backend/manager/models/image.py

@@ -798,7 +798,8 @@ def set_resource_limit(
         self._resources = resources
 
     def is_owned_by(self, user_id: UUID) -> bool:
-        return self.customized and self.labels["ai.backend.customized-image.owner"] == str(user_id)
+        owner_label = self.labels["ai.backend.customized-image.owner"]
+        return self.customized and owner_label.split(":")[1] == str(user_id)
 
     def to_dataclass(self) -> ImageData:
         from ai.backend.manager.data.image.types import ImageData