[FIX] schemeedit: Avoid replicated node renumbering on paste #464

Job	Run time
test (ubuntu-20.04, 3.9, PyQt5~=5.12.0)	1m 26s
test (ubuntu-20.04, 3.9, PyQt5~=5.14.0)	1m 27s
test (ubuntu-20.04, 3.10, PyQt5~=5.15.0)	57s
test (ubuntu-20.04, 3.11, PyQt5~=5.15.0)	50s
test (ubuntu-20.04, 3.11, PyQt6~=6.2.3 PyQt6-Qt6~=6.2.3)	1m 24s
test (ubuntu-22.04, 3.11, PyQt6~=6.5.0 PyQt6-Qt6~=6.5.0, glibc-tools)	52s
test (ubuntu-22.04, 3.12, PyQt6~=6.5.0 PyQt6-Qt6~=6.5.0, glibc-tools)	58s
test (macos-12, 3.9, PyQt5~=5.12.0)	1m 24s
test (macos-12, 3.9, PyQt5~=5.14.0)	1m 10s
test (macos-12, 3.10, PyQt5~=5.15.0)	1m 4s
test (macos-13, 3.11, PyQt5~=5.15.0)	1m 16s
test (macos-14, 3.11, PyQt6~=6.2.3 PyQt6-Qt6~=6.2.3)	52s
test (macos-latest, 3.11, PyQt6~=6.5.0 PyQt6-Qt6~=6.5.0)	46s
test (macos-latest, 3.12, PyQt6~=6.5.0 PyQt6-Qt6~=6.5.0)	45s
test (windows-2019, 3.9, PyQt5~=5.12.0)	1m 53s
test (windows-2019, 3.9, PyQt5~=5.15.0)	1m 56s
test (windows-2019, 3.10, PyQt5~=5.15.0)	1m 58s
test (windows-2019, 3.11, PyQt5~=5.15.0)	1m 28s
test (windows-2019, 3.11, PyQt6~=6.2.3 PyQt6-Qt6~=6.2.3)	2m 2s
test (windows-2019, 3.11, PyQt6~=6.5.0 PyQt6-Qt6~=6.5.0)	1m 43s
test (windows-2019, 3.12, PyQt6~=6.5.0 PyQt6-Qt6~=6.5.0)	2m 1s
	28m 12s

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