fix: add nullptr checks for new_pyobject_id [backport 2.9] (#10135) #54599

Job	Run time
test_unit (dd-lib-python-init-test-django)	3m 30s
test_unit (dd-lib-python-init-test-django-gunicorn)	3m 16s
test_unit (dd-lib-python-init-test-django-gunicorn-alpine)	3m 7s
test_unit (dd-lib-python-init-test-django-uvicorn)	3m 20s
test_unit (dd-lib-python-init-test-django-no-perms)	3m 12s
test_unit (dd-lib-python-init-test-django-pre-installed)	3m 22s
test_unit (dd-lib-python-init-test-django-unsupported-python)	3m 42s
build-and-publish-test-image / wait_for_package	10s
build-and-publish-test-image / build_push / build_push	13m 10s
test-runner-test (dd-lib-python-init-test-django)	2m 45s
test-runner-test (dd-lib-python-init-test-django-gunicorn)	3m 21s
test-runner-test (dd-lib-python-init-test-django-uvicorn)	3m 1s
	45m 56s

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