Drop deprecated `streamablehttp_client` #4051

Job	Run time
checks / readme-snippets	12s
checks / pre-commit	36s
checks / test (3.10, lowest-direct, ubuntu-latest)	48s
checks / test (3.14, lowest-direct, windows-latest)	2m 37s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 12s
checks / test (3.11, lowest-direct, ubuntu-latest)	45s
checks / test (3.10, lowest-direct, windows-latest)	2m 17s
checks / test (3.13, highest, ubuntu-latest)	41s
checks / test (3.12, highest, windows-latest)	3m 24s
checks / test (3.12, highest, ubuntu-latest)	51s
checks / test (3.10, highest, ubuntu-latest)	48s
checks / test (3.11, highest, windows-latest)	2m 26s
checks / test (3.13, lowest-direct, windows-latest)	2m 28s
checks / test (3.11, lowest-direct, windows-latest)	2m 25s
checks / test (3.12, lowest-direct, ubuntu-latest)	51s
checks / test (3.13, highest, windows-latest)	2m 32s
checks / test (3.10, highest, windows-latest)	2m 25s
checks / test (3.14, highest, ubuntu-latest)	1m 8s
checks / test (3.13, lowest-direct, ubuntu-latest)	43s
checks / test (3.11, highest, ubuntu-latest)	48s
checks / test (3.12, lowest-direct, windows-latest)	3m 22s
checks / test (3.14, highest, windows-latest)	2m 30s
	35m 49s

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