Deprecate `httpx` in favor of `httpx2` #2280

Job	Run time
checks / pre-commit	30s
checks / readme-snippets	14s
checks / test (3.10, locked, ubuntu-latest)	56s
checks / test (3.13, lowest-direct, windows-latest)	2m 47s
checks / test (3.10, lowest-direct, windows-latest)	3m 8s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.11, lowest-direct, windows-latest)	2m 44s
checks / test (3.13, locked, ubuntu-latest)	50s
checks / test (3.12, locked, windows-latest)	3m 34s
checks / test (3.10, locked, windows-latest)	2m 43s
checks / test (3.11, locked, windows-latest)	2m 29s
checks / test (3.12, locked, ubuntu-latest)	57s
checks / test (3.14, locked, windows-latest)	2m 34s
checks / test (3.13, locked, windows-latest)	2m 34s
checks / test (3.14, locked, ubuntu-latest)	2m 25s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.10, lowest-direct, ubuntu-latest)	57s
checks / test (3.11, locked, ubuntu-latest)	51s
checks / test (3.14, lowest-direct, windows-latest)	1m 58s
checks / test (3.12, lowest-direct, windows-latest)	3m 42s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 1s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 24s
all-green	2s
	40m 24s

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