[TEST] Fix lifetime issues in prometheus test utils #8503

Job	Run time
Bazel noexcept	20m 15s
Bazel asan config	13m 33s
Bazel nortti	28m 52s
Bazel on MacOS	27m 9s
Bazel	20m 28s
Bazel with async export	26m 53s
Bazel tsan config	19m 35s
Bazel valgrind	23m 48s
Bazel with external abseil	19m 42s
Benchmark	12m 16s
CMake test (with abseil)	6m 33s
CMake clang 14 (maintainer mode, async)	19m 17s
CMake clang 14 (maintainer mode, sync)	17m 10s
CMake do not install test (with otlp-exporter)	20m 59s
CMake gcc 4.8 (with otlp exporter)	14m 56s
CMake gcc 4.8 (without otlp exporter)	6m 43s
CMake gcc 12 (maintainer mode, async)	10m 37s
CMake gcc 12 (maintainer mode, C++11, async)	13m 26s
CMake gcc 12 (maintainer mode, sync)	10m 34s
CMake install test (with abseil)	5m 59s
CMake test (with modern protobuf,grpc and abseil)	30m 21s
CMake msvc (maintainer mode)	11m 0s
CMake test (with opentracing-shim)	6m 16s
CMake test (build shared libraries with otlp-exporter and static gRPC)	20m 58s
CMake test (with otlp-exporter)	29m 15s
CMake test (without otlp-exporter)	6m 52s
CMake C++20 test(Clang with libc++)	10m 57s
CMake C++20 test(GCC)	16m 37s
CMake test (without otlp-exporter and with async export)	6m 29s
Code coverage	13m 32s
Copyright	8s
DocFX check	1m 48s
Format	17s
markdown-lint	14s
misspell	5s
Plugin -> CMake	1m 4s
CMake -> exporter proto	23m 21s
Plugin -> CMake Windows	9m 6s
Bazel Windows	46m 18s
CMake (With async export) -> exporter proto	26m 27s
CMake -> exporter proto (Build as DLL)	17m 22s
	10h 17m 12s

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