Add `streamable_http_client` which accepts `httpx.AsyncClient` instead of `httpx_client_factory` #2897

Job	Run time
checks / readme-snippets	10s
checks / pre-commit	27s
checks / test (3.11, lowest-direct, windows-latest)	1m 37s
checks / test (3.10, lowest-direct, windows-latest)	1m 30s
checks / test (3.10, highest, ubuntu-latest)	36s
checks / test (3.10, lowest-direct, ubuntu-latest)	36s
checks / test (3.10, highest, windows-latest)	2m 2s
checks / test (3.11, lowest-direct, ubuntu-latest)	32s
checks / test (3.11, highest, ubuntu-latest)	35s
checks / test (3.12, lowest-direct, ubuntu-latest)	33s
checks / test (3.11, highest, windows-latest)	1m 27s
checks / test (3.12, lowest-direct, windows-latest)	1m 21s
checks / test (3.13, lowest-direct, ubuntu-latest)	35s
checks / test (3.12, highest, ubuntu-latest)	34s
checks / test (3.13, lowest-direct, windows-latest)	1m 39s
checks / test (3.13, highest, ubuntu-latest)	35s
checks / test (3.13, highest, windows-latest)	1m 23s
checks / test (3.12, highest, windows-latest)	2m 33s
	18m 45s

Provide feedback