[generator] fix import references

[nizox]

What does this PR do?

This PR fixes an inconsistency in the generator for reference imports. It aligns both get_references_for_model and type_to_typescript handling of objects with additionalProperties and properties fields.

The bug was discovered with this PR.

For the given specification:

components:
  schemas:
    ApplicationSecurityWafCustomRuleCreateAttributes:
      type: object
      description: "Create a new WAF custom rule."
      properties:
        ...
        tags:
          $ref: "#/components/schemas/ApplicationSecurityWafCustomRuleTags"

    ApplicationSecurityWafCustomRuleTags:
      type: object
      description: |-
        Tags associated with the WAF Custom Rule. The concatenation of category and type will form the security
        activity field associated with the traces.
      properties:
        category:
          $ref: "#/components/schemas/ApplicationSecurityWafCustomRuleTagsCategory"
        type:
          type: string
          description: The type of the WAF rule, associated with the category will form the security activity.
          example: "users.login.success"
      additionalProperties:
        type: string

Without the fix the following code was generated:

import { ApplicationSecurityWafCustomRuleCreateAttributesTags } from "./ApplicationSecurityWafCustomRuleCreateAttributesTags";

/**
 * Create a WAF custom rule.
*/
export class ApplicationSecurityWafCustomRuleCreateAttributes {
  ...
  /**
   * Tags associated with the WAF Custom Rule. The concatenation of category and type will form the security
   * activity field associated with the traces.
  */
  "tags": ApplicationSecurityWafCustomRuleTags;

After the fix, the generated and correct code:

import { ApplicationSecurityWafCustomRuleTags } from "./ApplicationSecurityWafCustomRuleTags";

/**
 * Create a WAF custom rule.
*/
export class ApplicationSecurityWafCustomRuleCreateAttributes {
  ...
  /**
   * Tags associated with the WAF Custom Rule. The concatenation of category and type will form the security
   * activity field associated with the traces.
  */
  "tags": ApplicationSecurityWafCustomRuleTags;

Additional Notes

Review checklist

Please check relevant items below:

• This PR includes all newly recorded cassettes for any modified tests.

• This PR does not rely on API client schema changes.

  • The CI should be fully passing.

• Or, this PR relies on API schema changes and this is a Draft PR to include tests for that new functionality.

  • Note: CI shouldn't be run on this Draft PR, as its expected to fail without the corresponding schema changes.