Change OTLP HTTP content_type default to binary #9242

Job	Run time
CMake clang 15 (maintainer mode, async)	13m 38s
CMake clang 15 (maintainer mode, sync)	13m 36s
CMake gcc 13 (maintainer mode, async)	6m 20s
CMake gcc 13 (maintainer mode, sync)	6m 44s
CMake test (without otlp-exporter)	4m 44s
CMake test (with abseil)	4m 54s
CMake clang 15 (maintainer mode, abiv2)	13m 44s
CMake msvc (maintainer mode)	8m 5s
CMake msvc (maintainer mode) with C++20	9m 0s
CMake test (with opentracing-shim)	4m 27s
CMake test (with otlp-exporter)	13m 41s
CMake C++14 test(GCC)	4m 11s
CMake C++17 test(GCC)	4m 38s
CMake C++20 test(Clang with libc++)	9m 48s
CMake C++20 test(GCC)	9m 36s
CMake C++23 test(Clang with libc++)	9m 22s
CMake C++23 test(GCC)	9m 43s
CMake test (without otlp-exporter and with async export)	5m 14s
Bazel asan config	14m 57s
Bazel noexcept	12m 12s
Bazel nortti	12m 28s
Bazel on MacOS	17m 24s
Bazel	12m 11s
Bazel with async export	12m 43s
Bazel tsan config	12m 37s
Bazel valgrind	14m 0s
Bazel with external abseil	12m 17s
CMake do not install test (with otlp-exporter)	13m 44s
CMake install test (with abseil)	4m 47s
CMake test (with modern protobuf,grpc and abseil)	18m 38s
CMake test (build shared libraries with otlp-exporter and static gRPC)	14m 10s
Plugin -> CMake	1m 0s
Benchmark	7m 52s
Code coverage	12m 7s
Copyright	7s
Format	14s
markdown-lint	8s
misspell	8s
CMake -> exporter proto	14m 36s
Bazel Windows	21m 47s
Plugin -> CMake Windows	6m 23s
CMake (With async export) -> exporter proto	12m 33s
CMake -> exporter proto (Build as DLL)	25m 14s
DocFX check	1m 16s
	7h 6m 58s

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