Pipeline for running optional firecracker integration tests

ci: Add secret hiding kernel to defaults buildkite

Failed in 16m 40s
:pipeline:
❓ m6a.metal al2023 linux_6.1./tools/devtool -y test --performance -c 1-10 -m 0 -- integration_tests/ -m 'no_block_pr and not nonci' --log-cli-level=INFO
Waited 2m 56s
·
Ran in 10m 35s
❓ m6a.metal ubuntu24 secret_hiding./tools/devtool -y test --performance -c 1-10 -m 0 -- integration_tests/ -m 'no_block_pr and not nonci' --log-cli-level=INFO
Waited 3m 0s
·
Ran in 10m 44s
Total Job Run Time: 3h 50m