ANDROID: Decrease severity of brya/kleaf warning

The previous message was confusing for users in the current state for
brya. See feedback in https://r.android.com/3362486

.

Bug: 379702641
Test: Build brya kernel; expect warning but no confirmation prompt
Test: Build non-brya kernel; expect no warning
Change-Id: I4e2d38d710efd527d2cb3238646fe001101d5ec3
Signed-off-by: Greg Edelston <gredelston@google.com>