chore : cleanup test expand headers

unit_tests/operator/Test_ExpandImpl.cpp

@@ -23,8 +23,6 @@
 #include "aidge/filler/Filler.hpp"
 #include "aidge/operator/Expand.hpp"
 
-#include "aidge/backend/cpu.hpp"
-
 using std::shared_ptr;
 
 using namespace Aidge;