Fix ACTs/Mobly conflicts

GDCert Real device tests were failing due to unknown command
"ensure-root".  This problem was due to unexpected mobly references
while running ACTs tests.  This was caused by the Blueberry instances of
the GDCert tests included in the acts directory.
Test: gd/cert/run
Bug: 193076304
Tag: #feature

Change-Id: I8768166abb2a5f204be2b9841902f580fec68040