Fix observable attributes drop (#2557) #9246

Job	Run time
Bazel noexcept	11m 40s
Bazel asan config	14m 31s
Bazel nortti	12m 17s
Bazel on MacOS	16m 28s
Bazel	12m 11s
Bazel with async export	12m 33s
Bazel tsan config	12m 50s
Bazel valgrind	14m 23s
Bazel with external abseil	12m 4s
Benchmark	7m 44s
CMake test (with abseil)	4m 38s
CMake clang 15 (maintainer mode, abiv2)	14m 5s
CMake clang 15 (maintainer mode, async)	14m 10s
CMake clang 15 (maintainer mode, sync)	14m 5s
CMake do not install test (with otlp-exporter)	13m 52s
CMake gcc 13 (maintainer mode, async)	7m 14s
CMake gcc 13 (maintainer mode, sync)	7m 10s
CMake install test (with abseil)	4m 25s
CMake test (with modern protobuf,grpc and abseil)	18m 56s
CMake msvc (maintainer mode)	8m 2s
CMake msvc (maintainer mode) with C++20	9m 8s
CMake test (with opentracing-shim)	4m 21s
CMake test (build shared libraries with otlp-exporter and static gRPC)	14m 11s
CMake test (with otlp-exporter)	13m 40s
CMake test (without otlp-exporter)	4m 36s
CMake C++14 test(GCC)	3m 58s
CMake C++17 test(GCC)	4m 49s
CMake C++20 test(Clang with libc++)	9m 36s
CMake C++20 test(GCC)	8m 29s
CMake C++23 test(Clang with libc++)	10m 25s
CMake C++23 test(GCC)	8m 29s
CMake test (without otlp-exporter and with async export)	4m 48s
Code coverage	11m 1s
Copyright	5s
DocFX check	33s
Format	11s
misspell	6s
markdown-lint	8s
Plugin -> CMake	1m 9s
CMake -> exporter proto	12m 7s
Bazel Windows	21m 22s
Plugin -> CMake Windows	6m 11s
CMake (With async export) -> exporter proto	12m 13s
CMake -> exporter proto (Build as DLL)	24m 55s
	6h 59m 49s

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