Fix incorrect TypingUnionType import check #9522

Job	Run time
🪟 Tests on Windows	5m 27s
💻 Generate test matrix	32s
📈 Benchmarks	3m 57s
✨ Lint	1m 34s
🔬 Tests on 3.12	2m 48s
🔬 Tests on 3.11	1m 52s
🔬 Tests on 3.10	1m 57s
🔬 Tests on 3.9	2m 5s
🔬 Tests on 3.8	2m 10s
🔬 Django tests on 3.11 (django=4.2.0)	1m 17s
🔬 Django tests on 3.11 (django=4.1.0)	1m 45s
🔬 Django tests on 3.11 (django=4.0.0)	1m 43s
🔬 Django tests on 3.11 (django=3.2.0)	1m 19s
🔬 Starlette tests on 3.11 (starlette=0.28.0)	1m 14s
🔬 Starlette tests on 3.11 (starlette=0.27.0)	1m 17s
🔬 Starlette tests on 3.11 (starlette=0.26.1)	1m 18s
🔬 Test integrations on 3.11 (integration=aiohttp)	1m 15s
🔬 Test integrations on 3.11 (integration=chalice)	1m 19s
🔬 Test integrations on 3.11 (integration=channels)	1m 27s
🔬 Test integrations on 3.11 (integration=fastapi)	1m 21s
🔬 Test integrations on 3.11 (integration=flask)	1m 35s
🔬 Test integrations on 3.11 (integration=sanic)	1m 18s
🔬 Test integrations on 3.11 (integration=starlite)	1m 43s
🔬 Pydantic tests on 3.11 (pydantic=1.10)	1m 40s
🔬 Pydantic tests on 3.11 (pydantic=2.0.3)	1m 30s
🔬 Pyright tests on 3.12	1m 53s
🔬 Pyright tests on 3.11	1m 48s
🔬 Pyright tests on 3.10	2m 13s
🔬 Pyright tests on 3.9	2m 13s
🔬 Pyright tests on 3.8	1m 49s
🔬 CLI tests on 3.12	1m 40s
🔬 CLI tests on 3.11	1m 25s
🔬 CLI tests on 3.10	1m 12s
🔬 CLI tests on 3.9	1m 14s
🔬 CLI tests on 3.8	1m 13s
	1h 2m 3s

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