DOC: Remove 10 year event announcement banner #1565

Job	Run time
py3.13 \| windows \| integration tests	29m 35s
py3.10 \| ubuntu \| integration tests	19m 8s
py3.13 \| ubuntu \| integration tests	17m 41s
mypy	4m 24s
py3.10 \| ubuntu \| unit tests	15m 35s
py3.13 \| macos \| integration tests	23m 15s
py3.13 \| windows \| unit tests	25m 30s
py3.11 \| ubuntu \| unit tests	14m 41s
py3.12 \| ubuntu \| unit tests	14m 41s
py3.13 \| macos \| unit tests	16m 3s
py3.13 \| ubuntu \| unit tests	14m 13s
merge-test-artifacts	0s
	3h 14m 46s

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