Fix issues with extractor dumpsys

Tracks and descriptions were added to their respective lists in
opposite order, so dumpsys could mix up the format and active
state for a given track. Also fix potential NULL pointer dereference.

Bug: 33179012
Bug: 23270724
Change-Id: I700d535da0e72f5641bf9257a34fdb5d5d068b12
(cherry picked from commit 50a6f88b)