[CI] Remove macOS 13 image from CI workflow (#2453)

[bunnysocks]

Did you read the Contributor Guide?

• Yes, I have read the Contributor Rules and Contributor Development Guide

Is this PR related to a ticket?

• Yes, and the PR name follows the format [GH-2453] my subject.
  Closes chore(ci): Remove MacOS 13 Image in CI #2453

What changes were proposed in this PR?

GitHub is deprecating the macos-13 image, which is currently used in our CI workflow (.github/workflows/python-extension.yml).

This PR replaces macos-13 with macos-15, which is the new default runner image on GitHub Actions.
This ensures continued CI compatibility after macOS 13 is removed on Dec 4, 2025.

How was this patch tested?

• Verified YAML syntax locally.
• Pushed branch to trigger GitHub Actions CI run.
• Confirmed that all jobs (Ubuntu, Windows, macOS) pass successfully.

Did this PR include necessary documentation updates?

• No, this PR does not affect any public API so no need to change the documentation.

[Kontinuation]

macOS CI for shapely 1.7 fails, but I'm OK with deprecating it. Awaiting opinions of other maintainers.

[jiayuasu]

I am also fine removing Shapely 1.7 test and only run 1.8 and 2.0 test. Please go ahead and update the PR.

[bunnysocks]

updated the PR — removed Shapely 1.7 tests as suggested.
The workflow now only runs Shapely 1.8 and 2.0 tests.