fix #17258 - use model class only if it is generated (#17490)

* fix  #16797 and #15796 spring child constructor missing parent params

* root cause and update the DefaultCodegen.java to add missing property when with multi inheritance

* rollback SpringCodegen.java

* update samples

* rollback with master cause #16992 fixed this issue too

* still using orignal design

* catchup master

* catchup master

* catchup master

* fix

* add tests

---------

Co-authored-by: dabdirb <dabdirb@gmail.com>

samples/client/petstore/java/native-async/api/openapi.yaml

@@ -952,6 +952,25 @@ paths:
       - fake
       x-content-type: application/x-www-form-urlencoded
       x-accepts: application/json
+  /fake/additionalProperties-reference:
+    post:
+      description: ""
+      operationId: testAdditionalPropertiesReference
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/FreeFormObject'
+        description: request body
+        required: true
+      responses:
+        "200":
+          description: successful operation
+      summary: test referenced additionalProperties
+      tags:
+      - fake
+      x-content-type: application/json
+      x-accepts: application/json
   /fake/inline-additionalProperties:
     post:
       description: ""
@@ -1775,6 +1794,10 @@ components:
             type: string
           type: array
       type: object
+    FreeFormObject:
+      additionalProperties: true
+      description: A schema consisting only of additional properties
+      type: object
     OuterEnum:
       enum:
       - placed