Use GitHub hosted Ubuntu arm64 runners instead of CircleCI #2740

Job	Run time
lint_and_validate_rendered_templates	8s
lint_and_validate_rendered_templates	10s
lint_and_validate_templates_with_schema	8s
lint_and_validate_templates_with_schema	9s
lint_and_validate_templates_with_schema (v3.5.0)	12s
lint_and_validate_templates_with_schema (v3.5.0)	7s
lint_shell_scripts	43s
lint_shell_scripts	37s
test (latest, install, ubuntu-24.04-arm)	2m 31s
test (latest, install, ubuntu-24.04-arm)	2m 1s
test (stable, install, --set hub.image.name=quay.io/jupyterhub/k8s-hub-slim --set prePuller.hook....	2m 22s
test (stable, install, --set hub.image.name=quay.io/jupyterhub/k8s-hub-slim --set prePuller.hook....	1m 55s
test (v1.31, install, --set hub.existingSecret=test-hub-existing-secret --set proxy.secretToken=a...	1m 54s
test (v1.31, install, --set hub.existingSecret=test-hub-existing-secret --set proxy.secretToken=a...	1m 54s
test (v1.30, upgrade, stable, --set proxy.secretToken=aaaa1111 --set hub.cookieSecret=bbbb2222 --...	2m 21s
test (v1.30, upgrade, stable, --set proxy.secretToken=aaaa1111 --set hub.cookieSecret=bbbb2222 --...	2m 52s
test (v1.29, upgrade, dev, --set proxy.secretToken=aaaa1111 --set hub.db.type=sqlite-pvc --set si...	2m 2s
test (v1.29, upgrade, dev, --set proxy.secretToken=aaaa1111 --set hub.db.type=sqlite-pvc --set si...	2m 35s
test (v1.28, upgrade, 2.0.0, --set proxy.secretToken=aaaa1111 --set hub.cookieSecret=bbbb2222 --s...	2m 30s
test (v1.28, upgrade, 2.0.0, --set proxy.secretToken=aaaa1111 --set hub.cookieSecret=bbbb2222 --s...	3m 17s
	30m 28s

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