fix(example): remove res.Data access in Example_listModels after pagination regen

[LukasParke]

Summary

Fixes the sdk-build-check (go) CI failure blocking PR #27246.

The pagination regeneration removed .Data from the models list response type, but Example_listModels in example_test.go still referenced res.Data, causing a build error.

Change

example_test.go — Example_listModels:

// Before
if res != nil && len(res.Data) > 0 {
    fmt.Printf("Found %d models\n", len(res.Data))
    fmt.Printf("First model: %s\n", res.Data[0].Name)
}

// After
if res != nil {
    fmt.Println("Successfully fetched models")
}

The other res.Data references in the file (single-model fetch, providers list) are in different functions with different response types that still carry .Data — those are untouched.