[trainers] Fixed the SiameseTrainer validation

6 jobs for tf-slim in 11 minutes and 48 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_27 #78896
conda-linux

00:02:34

passed build_linux_35 #78897
conda-linux

00:03:04

passed build_linux_36 #78898
conda-linux

00:03:08

 
  Test
passed test_linux_27 #78899
conda-linux

00:08:12

passed test_linux_35 #78900
conda-linux

00:08:17

passed test_linux_36 #78901
conda-linux

00:08:35