Not to use any() to verify DataStallDetectionStats

Build a empty DataStallDetectionStats object instead of use
any() to do the verification to prevent NPE while trying to
write the metrics.

Bug: 120452078
Test: atest NetworkStackTests
Change-Id: Ib9f3e56195a539a5ca4826b4aad0e38945a9a3a7
1 file changed