http_client.c: fix tracing error response message bodies #2285

Job	Run time
check_docs	57s
check_update	1m 19s
check-ansi	2m 37s
address_ub_sanitizer	10m 54s
basic_clang	5m 59s
basic_gcc	5m 47s
minimal	2m 38s
no-deprecated	5m 21s
non-caching	12m 36s
no-shared-macos (macos-13)	8m 6s
no-shared-macos (macos-14)	3m 47s
no-shared-ubuntu	4m 37s
self-hosted	0s
enable_non-default_options	4m 40s
external-test-cf-quiche	3m 41s
external-test-pyca (1.51.0, 3.9)	7m 16s
external-tests	11m 23s
full_featured	6m 10s
fuzz_tests	3m 4s
legacy	4m 48s
memory_sanitizer	19m 1s
no-legacy	5m 52s
out-of-readonly-source-and-install-macos (macos-13)	16m 27s
out-of-readonly-source-and-install-ubuntu	7m 36s
out-of-readonly-source-and-install-macos (macos-14)	6m 23s
threads_sanitizer	5m 0s
	2h 45m 59s

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