Add support for async generator injections #1280

Job	Run time
Run tests with different pydantic versions	3m 21s
Run tests with coverage	2m 59s
Run tests (3.9)	1m 55s
Run tests (3.11)	1m 45s
Run tests (3.10)	1m 54s
Run tests (3.13)	2m 3s
Run linters (flake8)	1m 31s
Run linters (pydocstyle)	1m 28s
Run tests (3.8)	1m 50s
Run tests (3.12)	1m 57s
Run linters (pylint)	1m 44s
Run linters (mypy)	1m 36s
	24m 3s

Provide feedback