Replace httpx and httpx-sse with httpx2 #3472

Job	Run time
checks / readme-snippets	18s
checks / test (3.12, locked, ubuntu-latest)	1m 38s
checks / pre-commit	51s
checks / test (3.14, locked, ubuntu-latest)	1m 22s
checks / test (3.10, locked, ubuntu-latest)	1m 20s
checks / test (3.13, locked, windows-latest)	1m 51s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 30s
checks / docs	37s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 21s
checks / test (3.14, locked, windows-latest)	1m 55s
checks / test (3.11, locked, ubuntu-latest)	1m 6s
checks / test (3.13, lowest-direct, windows-latest)	1m 53s
checks / test (3.13, locked, ubuntu-latest)	1m 8s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 14s
checks / test (3.14, lowest-direct, windows-latest)	1m 51s
checks / test (3.11, lowest-direct, windows-latest)	1m 20s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 8s
checks / test (3.10, lowest-direct, windows-latest)	1m 58s
checks / test (3.11, locked, windows-latest)	1m 35s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 21s
checks / test (3.12, lowest-direct, windows-latest)	2m 1s
checks / test (3.10, locked, windows-latest)	2m 0s
checks / test (3.12, locked, windows-latest)	1m 42s
all-green	3s
	33m 3s

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