detect/http: fix compile warning in body tests #9307

Job	Run time
Prepare cbindgen	17s
Prepare dependencies	53s
AlmaLinux 8	5m 35s
AlmaLinux 9 (no jansson)	1m 9s
AlmaLinux 9	12m 22s
AlmaLinux 9 Test Templates	5m 7s
Debian 10	7m 28s
Debian 11 (xdp)	7m 27s
Debian 12	25m 23s
Debian 12 Dist Builder	4m 21s
Debian 12 MSRV	22m 25s
Fedora 38 (clang, debug, asan, wshadow, rust-strict, systemd)	57m 9s
Fedora 38 (gcc, debug, asan, wshadow, rust-strict)	8m 30s
Fedora 38 (Suricata Verify codecov)	7m 33s
Fedora 39 (clang, debug, asan, wshadow, rust-strict, systemd)	7m 53s
Fedora 39 (gcc, debug, asan, wshadow, rust-strict)	7m 57s
Fedora 39 (non-root, debug, clang, asan, wshadow, rust-strict, systemd)	7m 5s
MacOS Latest	13m 7s
Ubuntu 20.04 (-DNDEBUG)	8m 56s
Ubuntu 22.04 (fuzz corpus coverage)	12m 21s
Ubuntu 22.04 (unittests coverage)	6m 16s
Ubuntu 22.04 (Debug Validation)	9m 10s
Ubuntu 22.04 (DPDK Build) (22.11.3)	13m 52s
Ubuntu 22.04 (DPDK Build) (21.11.5)	11m 31s
Ubuntu 22.04 (Fuzz)	6m 8s
Ubuntu 22.04 (Netmap build)	3m 29s
Windows MSYS2 MINGW64 (libpcap)	25m 30s
Ubuntu 22.04 (DPDK Build) (20.11.9)	10m 3s
Ubuntu 22.04 (DPDK Build) (19.11.14)	8m 53s
Windows MSYS2 MINGW64 (NPcap)	24m 43s
Windows MSYS2 MINGW64 (WinDivert)	12m 45s
CentOS Stream 8	5m 29s
CentOS Stream 9	6m 1s
CentOS 7	14m 34s
Ubuntu 20.04 (unsupported rust)	1m 30s
	6h 22m 52s

Provide feedback