After the kernel roll to linux-gcp-5.15-5.15.0-1051.59_20.04.1,
basic_ubuntu::test_snap_preseed_optimized began failuring due to
a preseed mismatch. This change adds a 5.15 apparmor configuration
to the focal branch.
(cherry picked from commit 76628691f5e584bde009f71d05c2057a624445d5)
