Remove unused properties:
* `FieldColorModeId.PaletteSaturated`: It doesn't exist and it is not a valid palette.
* `VariableModel.rootStateKey`: It is not persisted in the DB, so it shouldn't be in the schema. It is a property only used in the frontend to store the Redux store key.
* `VariableModel.error`: It is not persisted in the DB, so it shouldn't be in the schema. It is a property only used in the frontend to store fetching errors.
* `Panel.thresholds`: old property only existing in previous versions of the dashboard schema.
* `Panel.timeRegions`: old property only existing in previous versions of the dashboard schema.
Ryan McKinley
Selene
sam boyer
Tania
Ivan Ortega Alba