Ensure preset segments are lists (#1420)

src/wled/models.py

@@ -612,6 +612,15 @@ class Preset(BaseModel):
     )
     """Segments are individual parts of the LED strip."""
 
+    @classmethod
+    def __pre_deserialize__(cls, d: dict[Any, Any]) -> dict[Any, Any]:
+        """Pre deserialize hook for Preset object."""
+        # If the segment is a single value, we will convert it to a list.
+        if "seg" in d and not isinstance(d["seg"], list):
+            d["seg"] = [d["seg"]]
+
+        return d
+
     @classmethod
     def __post_deserialize__(cls, obj: Preset) -> Preset:
         """Post deserialize hook for Preset object."""