[python] Add mock API test for Azure_Core_Page_withRelativeNextLink scenario

[Copilot]

Adds Python SDK test coverage for the Azure_Core_Page_withRelativeNextLink Spector scenario (Azure/typespec-azure#3922), which validates that the generated client correctly resolves relative nextLink URLs against the service endpoint during pagination.

• Sync + async tests in test_azure_core_page.py / test_azure_core_page_async.py paginating two pages and asserting id, name, and etag per item
• Dependency bump: @azure-tools/azure-http-specs → 0.1.0-alpha.38-dev.2 to pick up the new scenario

def test_list_with_relative_next_link(client: PageClient):
    result = list(client.with_relative_next_link())
    assert len(result) == 2
    assert result[0].id == 1
    assert result[0].name == "User1"
    assert result[0].etag == "11bdc430-65e8-45ad-81d9-8ffa60d55b59"
    assert result[1].id == 2
    assert result[1].name == "User2"
    assert result[1].etag == "11bdc430-65e8-45ad-81d9-8ffa60d55b59"

Original prompt

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This section details on the original issue you should resolve

<issue_title>[python] add test case for Azure/typespec-azure#3922</issue_title>
<issue_description>follow skill https://github.com/microsoft/typespec/blob/main/.github/skills/python-sdk-spector-mock-api-tests/SKILL.md to write test case for Azure/typespec-azure#3922</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [python] add test case for https://github.com/Azure/typespec-azure/pull/3922 #9849

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