derived class with additional data field are missing it

[baywet]

The following yaml description results in the alert model missing the additional data field.
This is because it's conflicting with the additional data field the parent model gets from standard generation.

This method needs to have a special case to handle that, and when the custom property name is "additionalData" add a prefix like we do when some fields conflict with native language primitives

kiota/src/Kiota.Builder/KiotaBuilder.cs

Line 1185 in b3bd7a0

private CodeProperty? CreateProperty(string childIdentifier, string childType, OpenApiSchema? propertySchema = null, CodeTypeBase? existingType = null, CodePropertyKind kind = CodePropertyKind.Custom)

openapi: 3.0.1
info:
  title: OData Service for namespace microsoft.graph
  description: This OData service is located at https://graph.microsoft.com/v1.0
  version: v1.0
  x-ms-generated-by:
    toolName: Microsoft.OpenApi.OData
    toolVersion: 1.0.9.0
servers:
  - url: https://graph.microsoft.com/v1.0
paths:
  '/security/alerts_v2/{alert-id}':
    description: Provides operations to manage the alerts_v2 property of the microsoft.graph.security entity.
    get:
      tags:
        - security.alert
      summary: Get alert
      description: Get the properties and relationships of an alert object.
      externalDocs:
        description: Find more info here
        url: https://learn.microsoft.com/graph/api/security-alert-get?view=graph-rest-1.0
      operationId: security.GetAlerts_v2
      responses:
        2XX:
          description: Retrieved navigation property
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/microsoft.graph.security.alert'
      x-ms-docs-operation-type: operation
components:
    microsoft.graph.entity:
      title: entity
      required:
        - '@odata.type'
      type: object
      properties:
        id:
          type: string
          description: The unique identifier for an entity. Read-only.
        '@odata.type':
          type: string
    microsoft.graph.security.dictionary:
      title: dictionary
      required:
        - '@odata.type'
      type: object
      properties:
        '@odata.type':
          type: string
    microsoft.graph.security.alert:
      allOf:
        - $ref: '#/components/schemas/microsoft.graph.entity'
        - title: alert
          required:
            - '@odata.type'
          type: object
          properties:
            actorDisplayName:
              type: string
              description: The adversary or activity group that is associated with this alert.
              nullable: true
            additionalData:
              anyOf:
                - $ref: '#/components/schemas/microsoft.graph.security.dictionary'
                - type: object
                  nullable: true

[baywet]

Additionally, the unit test could be added here similar to this test but with the provided repro OpenAPI description.

This issue has originally been reported by @tiananguyen (MSFT) who's currently checking with her management how to proceed (they are blocked by the bug)