Fix/multipart 413 pr #6279

Job	Run time
mypy	1m 7s
validate	14s
slotscheck	19s
pyright	33s
test_typing_extensions (4.13.1)	22s
test_typing_extensions (4.12.1)	19s
test_typing_extensions (latest)	23s
Test Minimal Pydantic 1 application	26s
Test server integration (uvicorn>=0.27.0)	56s
Test server integration (uvicorn<0.27.0)	46s
Test Minimal Application with Base Dependencies	18s
test-platform-compat	0s
test (3.13) / test	1m 43s
test (3.10) / test	1m 56s
test (3.11) / test	1m 59s
test (3.12) / test	1m 56s
test (3.9) / test	1m 59s
build-docs	0s
upload-test-coverage	0s
test_success	4s
codeql	0s
	15m 20s

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