[DOC] Fix OTLP documentation: Default endpoint is wrong for OTLP/HTTP #9260

Job	Run time
Bazel noexcept	13m 6s
Bazel asan config	15m 30s
Bazel nortti	13m 13s
Bazel on MacOS	32m 8s
Bazel	12m 40s
Bazel with async export	12m 53s
Bazel tsan config	13m 39s
Bazel valgrind	14m 26s
Bazel with external abseil	12m 25s
Benchmark	9m 16s
CMake test (with abseil)	5m 0s
CMake clang 15 (maintainer mode, abiv2)	15m 56s
CMake clang 15 (maintainer mode, async)	15m 10s
CMake clang 15 (maintainer mode, sync)	15m 18s
CMake do not install test (with otlp-exporter)	14m 26s
CMake gcc 13 (maintainer mode, sync)	6m 49s
CMake gcc 13 (maintainer mode, async)	9m 26s
CMake test (with modern protobuf,grpc and abseil)	20m 6s
CMake install test (with abseil)	4m 53s
CMake msvc (maintainer mode)	9m 23s
CMake msvc (maintainer mode) with C++20	9m 14s
CMake test (with opentracing-shim)	6m 12s
CMake test (build shared libraries with otlp-exporter and static gRPC)	14m 4s
CMake test (with otlp-exporter)	14m 36s
CMake test (without otlp-exporter)	5m 17s
CMake C++14 test(GCC)	4m 14s
CMake C++17 test(GCC)	5m 42s
CMake C++20 test(Clang with libc++)	11m 0s
CMake C++20 test(GCC)	9m 0s
CMake C++23 test(Clang with libc++)	10m 31s
CMake C++23 test(GCC)	10m 33s
CMake test (without otlp-exporter and with async export)	6m 48s
Code coverage	12m 54s
Copyright	7s
DocFX check	1m 4s
Format	41s
markdown-lint	56s
misspell	14s
Plugin -> CMake	2m 18s
CMake -> exporter proto	15m 8s
Plugin -> CMake Windows	8m 17s
Bazel Windows	25m 55s
CMake (With async export) -> exporter proto	13m 10s
CMake -> exporter proto (Build as DLL)	32m 39s
	8h 6m 17s

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