Change OTLP HTTP content_type default to binary #9243

Job	Run time
CMake clang 15 (maintainer mode, sync)	14m 7s
CMake gcc 13 (maintainer mode, async)	6m 42s
CMake test (without otlp-exporter)	5m 44s
CMake test (with abseil)	4m 40s
CMake clang 15 (maintainer mode, abiv2)	14m 1s
CMake clang 15 (maintainer mode, async)	14m 6s
CMake gcc 13 (maintainer mode, sync)	6m 53s
CMake msvc (maintainer mode)	7m 26s
CMake msvc (maintainer mode) with C++20	8m 39s
CMake test (with opentracing-shim)	4m 13s
CMake C++14 test(GCC)	4m 57s
CMake test (without otlp-exporter and with async export)	4m 45s
Bazel	12m 53s
Bazel with async export	12m 59s
Bazel valgrind	15m 23s
Bazel with external abseil	12m 27s
CMake do not install test (with otlp-exporter)	14m 4s
CMake install test (with abseil)	4m 28s
CMake test (with modern protobuf,grpc and abseil)	19m 46s
CMake test (build shared libraries with otlp-exporter and static gRPC)	13m 54s
CMake test (with otlp-exporter)	14m 17s
CMake C++17 test(GCC)	4m 53s
CMake C++20 test(Clang with libc++)	10m 58s
CMake C++20 test(GCC)	8m 43s
CMake C++23 test(Clang with libc++)	9m 29s
CMake C++23 test(GCC)	8m 57s
Plugin -> CMake	56s
Bazel asan config	14m 56s
Bazel noexcept	12m 2s
Bazel nortti	11m 57s
Bazel on MacOS	14m 23s
Bazel tsan config	12m 32s
Benchmark	8m 18s
Code coverage	12m 32s
Copyright	5s
Format	14s
markdown-lint	14s
misspell	8s
CMake -> exporter proto	12m 36s
Bazel Windows	20m 37s
Plugin -> CMake Windows	7m 11s
CMake (With async export) -> exporter proto	12m 3s
CMake -> exporter proto (Build as DLL)	21m 54s
DocFX check	43s
	7h 2m 45s

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