Fix missing check of hidl return status

closeAllSessions() was calling into the hidl interface closeSession
directly, and neglected to check the return status which resulted in
an abort. Instead, call the DrmHal::closeSession() method which handles
the hidl return status correctly.

Test: gts media tests

bug:72400509
Change-Id: I444be998702aeaca2905ddf560a5138d5775a316