test-capability: CAP_LINUX_IMMUTABLE is not available in unprivileged containers

test-capability: CAP_LINUX_IMMUTABLE is not available in unprivileged containers

have ambient caps: yes
Capabilities:cap_chown,cap_dac_override,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_net_bind_service,cap_net_raw,cap_sys_chroot,cap_mknod,cap_audit_write,cap_setfcap=ep
Failed to drop auxiliary groups list: Operation not permitted
Failed to change group ID: Operation not permitted
Capabilities:cap_dac_override,cap_net_raw=ep
Capabilities:cap_dac_override=ep
Successfully forked off '(getambient)' as PID 12505.
Skipping PR_SET_MM, as we don't have privileges.
Ambient capability cap_linux_immutable requested but missing from bounding set, suppressing automatically.
Assertion 'x < 0 || FLAGS_SET(c, UINT64_C(1) << CAP_LINUX_IMMUTABLE)' failed at src/test/test-capability.c:273, function test_capability_get_ambient(). Aborting.
(getambient) terminated by signal ABRT.
src/test/test-capability.c:258: Assertion failed: expected "r" to succeed, but got error: Protocol error

Partially fixes #35552