snapuserd_test: skip test if dm-user kernel driver is absent

Bug: 357487459
Test: snapuserd_test
Signed-off-by: Akilesh Kailash <akailash@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:a880e5675b747b9f3d5631b656e0a7408edc6ad7)
Merged-In: I8458f223fc35fcfa042588e67a30c5bb273b0277
Change-Id: I8458f223fc35fcfa042588e67a30c5bb273b0277
4 files changed