chore(deps): bump python in /.buildkite

Bumps python from 3.13.6-bookworm to 3.13.7-bookworm.

---
updated-dependencies:
- dependency-name: python
  dependency-version: 3.13.7-bookworm
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.buildkite/Dockerfile

@@ -1,6 +1,6 @@
 FROM ruby:3.4.5-slim-bookworm AS ruby
 FROM cypress/included:14.5.3 AS cypress
-FROM python:3.13.6-bookworm AS python
+FROM python:3.13.7-bookworm AS python
 
 FROM golang:1.24.6-bookworm AS golang