Fix nested flowsheet time domain construction #7187

Job	Run time
Check Spelling	7s
Compatibility tests	4m 43s
Check code formatting (Black)	30s
Pylint	4m 22s
Build Sphinx docs	5m 29s
pytest (py3.9/linux)	20m 39s
pytest (py3.9/win64)	29m 50s
pytest (py3.10/linux)	13m 41s
pytest (py3.10/win64)	32m 18s
pytest (py3.11/linux)	19m 44s
pytest (py3.11/win64)	44m 0s
pytest (py3.12/linux)	12m 54s
pytest (py3.12/win64)	31m 20s
Upload coverage report (Codecov)	0s
	3h 39m 37s

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