Update issue_21587 unit test to catch the Array<Model> case

Author: cgual-omnidian

modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java

@@ -441,6 +441,7 @@ public void testOneOfModelsImportNonPrimitiveTypes() throws IOException {
         );
         TestUtils.assertFileContains(testResponse, "import type { OptionOne } from './OptionOne'");
         TestUtils.assertFileContains(testResponse, "import type { OptionTwo } from './OptionTwo'");
+        TestUtils.assertFileContains(testResponse, "import type { OptionThree } from './OptionThree'");
     }
 
     private static File generate(

modules/openapi-generator/src/test/resources/3_0/typescript-fetch/issue_21587.yaml

@@ -20,6 +20,9 @@ paths:
                 oneOf:
                   - $ref: '#/components/schemas/OptionOne'
                   - $ref: '#/components/schemas/OptionTwo'
+                  - type: array
+                    items:
+                      $ref: '#/components/schemas/OptionThree'
                   - type: string
                     enum:
                       - "fixed-value-a"
@@ -66,4 +69,11 @@ components:
       title: OptionTwo
       properties:
         propTwo:
-          type: string
+          type: string
+    OptionThree:
+      type: object
+      title: OptionThree
+      properties:
+        propThree:
+          type: boolean
+      additionalProperties: true