ensure backwards compatibility of credits price

Author: bisgaard-itis

services/api-server/src/simcore_service_api_server/models/schemas/backwards_compatibility.py

@@ -0,0 +1,18 @@
+# Models added here "cover" models from within the deployment in order to restore backwards compatibility
+
+from typing import Annotated
+
+from models_library.api_schemas_webserver.product import GetCreditPrice
+from models_library.basic_types import NonNegativeDecimal
+from pydantic import Field, NonNegativeFloat, PlainSerializer
+
+
+class GetCreditPriceApiServer(GetCreditPrice):
+    usd_per_credit: Annotated[
+        NonNegativeDecimal,
+        PlainSerializer(float, return_type=NonNegativeFloat, when_used="json"),
+    ] | None = Field(
+        ...,
+        description="Price of a credit in USD. "
+        "If None, then this product's price is UNDEFINED",
+    )