fixed: do not enable tensorflow test without tensorflow on the system

tensorflow is too heavy to drag in as a dependency for everyone

pythonIntegrationTests.cmake

@@ -1,5 +1,11 @@
 file(MAKE_DIRECTORY ${PROJECT_BINARY_DIR}/tests/integration/HybridNewton)
-
+execute_process(
+  COMMAND "${Python3_EXECUTABLE}" -c "import tensorflow"
+  RESULT_VARIABLE PYTHON_HAS_TENSORFLOW
+  OUTPUT_QUIET
+  ERROR_QUIET
+)
+if(PYTHON_HAS_TENSORFLOW EQUAL 0)
   add_test(NAME
             HybridNewton
            COMMAND
@@ -20,3 +26,4 @@ if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.22)
                            "${modifications}"
     )
   endif()
+endif()