http_client.c: fix tracing error response message bodies #2226

Job	Run time
check_docs	1m 0s
check_update	1m 21s
check-ansi	2m 37s
basic_gcc	5m 49s
basic_clang	5m 56s
minimal	2m 42s
no-deprecated	5m 15s
no-shared-ubuntu	4m 38s
self-hosted	0s
address_ub_sanitizer	10m 54s
enable_non-default_options	5m 4s
fuzz_tests	3m 6s
memory_sanitizer	18m 12s
non-caching	12m 33s
no-shared-macos (macos-13)	7m 32s
threads_sanitizer	5m 38s
no-shared-macos (macos-14)	4m 47s
external-test-cf-quiche	3m 44s
external-test-pyca (1.51.0, 3.9)	6m 5s
external-tests	11m 8s
full_featured	6m 13s
legacy	4m 56s
no-legacy	5m 46s
out-of-readonly-source-and-install-macos (macos-13)	14m 21s
out-of-readonly-source-and-install-ubuntu	7m 49s
out-of-readonly-source-and-install-macos (macos-14)	7m 14s
	2h 44m 20s

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