update test_setBatchSTC without unique call to compute nb slices

Author: marcobarilari

tests/tests_batches/preproc/test_setBatchSTC.m

@@ -181,7 +181,7 @@ function test_setBatchSTC_error_invalid_input_time()
 
 function expectedBatch = returnExpectedBatch(sliceOrder, referenceSlice, TR)
 
-  nbSlices = length(unique(sliceOrder));
+  nbSlices = length(sliceOrder);
   TA = getAcquisitionTime(sliceOrder, TR);
 
   temporal.st.nslices = nbSlices;