docs: generate OAS for v2 (#7883)

www/apps/api-reference/specs/store/components/responses/400_error.yaml

@@ -1,14 +1,10 @@
-description: Client Error or Multiple Errors
+description: Client Error
 content:
   application/json:
     schema:
-      oneOf:
-        - $ref: ../schemas/Error.yaml
-        - $ref: ../schemas/MultipleErrors.yaml
+      $ref: ../schemas/Error.yaml
     examples:
       not_allowed:
         $ref: ../examples/not_allowed_error.yaml
       invalid_data:
         $ref: ../examples/invalid_data_error.yaml
-      MultipleErrors:
-        $ref: ../examples/multiple_errors.yaml