[DOC] Fix OTLP documentation: Default endpoint is wrong for OTLP/HTTP #9251

Job	Run time
CMake gcc 13 (maintainer mode, async)	7m 12s
CMake clang 15 (maintainer mode, abiv2)	16m 27s
CMake clang 15 (maintainer mode, async)	14m 19s
CMake clang 15 (maintainer mode, sync)	14m 11s
CMake gcc 13 (maintainer mode, sync)	6m 39s
CMake msvc (maintainer mode)	8m 29s
CMake msvc (maintainer mode) with C++20	9m 54s
CMake test (without otlp-exporter)	4m 39s
CMake test (with abseil)	5m 8s
CMake do not install test (with otlp-exporter)	14m 40s
CMake test (with modern protobuf,grpc and abseil)	18m 17s
CMake test (with opentracing-shim)	4m 17s
CMake test (build shared libraries with otlp-exporter and static gRPC)	14m 12s
CMake test (with otlp-exporter)	13m 50s
CMake C++14 test(GCC)	4m 45s
CMake C++17 test(GCC)	5m 2s
CMake C++20 test(Clang with libc++)	9m 36s
CMake C++20 test(GCC)	9m 2s
CMake C++23 test(GCC)	10m 48s
CMake C++23 test(Clang with libc++)	10m 4s
CMake test (without otlp-exporter and with async export)	5m 20s
Bazel asan config	15m 8s
Bazel noexcept	11m 47s
Bazel nortti	12m 27s
Bazel on MacOS	31m 11s
Bazel	13m 47s
Bazel with async export	12m 6s
Bazel tsan config	12m 33s
Bazel valgrind	14m 35s
Bazel with external abseil	12m 25s
Benchmark	8m 11s
CMake install test (with abseil)	4m 53s
Copyright	4s
Format	12s
Plugin -> CMake	1m 54s
CMake -> exporter proto	13m 0s
DocFX check	1m 13s
Code coverage	12m 40s
markdown-lint	6s
misspell	6s
Bazel Windows	19m 19s
Plugin -> CMake Windows	7m 38s
CMake (With async export) -> exporter proto	14m 37s
CMake -> exporter proto (Build as DLL)	25m 7s
	7h 31m 50s

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