examples: Fix ADER notebook numbering #7038

Job	Run time
pytest-ubuntu-py311-gcc11-noomp-base	49m 56s
pytest-ubuntu-py311-gcc11-noomp-adjoint	38m 28s
pytest-ubuntu-py312-gcc12-omp-base	1h 7m 15s
pytest-ubuntu-py312-gcc12-omp-adjoint	51m 29s
pytest-ubuntu-py39-gcc7-omp-base	52m 54s
pytest-ubuntu-py39-gcc7-omp-adjoint	41m 3s
pytest-ubuntu-py310-gcc10-noomp-base	51m 29s
pytest-ubuntu-py310-gcc10-noomp-adjoint	39m 8s
pytest-ubuntu-py312-gcc13-omp-base	1h 7m 14s
pytest-ubuntu-py312-gcc13-omp-adjoint	50m 0s
pytest-ubuntu-py39-gcc9-omp-base	52m 30s
pytest-ubuntu-py39-gcc9-omp-adjoint	39m 47s
pytest-osx-py312-clang-omp-base	48m 6s
pytest-docker-py39-gcc-omp-base	46m 3s
pytest-docker-py39-gcc-omp-adjoint	36m 7s
pytest-docker-py39-icx-omp-base	37m 49s
pytest-docker-py39-icx-omp-adjoint	34m 54s
	13h 24m 12s

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