Remove duplicate install command in CMakeLists.txt for api (#2474) #2

Job	Run time
CMake clang 14 (maintainer mode, abiv2)	13m 57s
CMake clang 14 (maintainer mode, async)	13m 59s
CMake clang 14 (maintainer mode, sync)	14m 19s
CMake gcc 12 (maintainer mode, async)	7m 56s
CMake gcc 12 (maintainer mode, sync)	8m 26s
CMake msvc (maintainer mode)	7m 46s
CMake msvc (maintainer mode) with C++20	8m 17s
CMake test (without otlp-exporter)	4m 33s
CMake test (with abseil)	4m 31s
CMake do not install test (with otlp-exporter)	13m 36s
CMake install test (with abseil)	4m 29s
CMake test (with modern protobuf,grpc and abseil)	18m 0s
CMake test (with opentracing-shim)	4m 35s
CMake test (with otlp-exporter)	14m 17s
CMake C++14 test(GCC)	4m 29s
CMake C++17 test(GCC)	4m 40s
CMake C++20 test(Clang with libc++)	9m 43s
CMake C++20 test(GCC)	8m 12s
CMake test (without otlp-exporter and with async export)	4m 33s
Bazel asan config	2m 15s
Bazel noexcept	1m 20s
Bazel nortti	1m 38s
Bazel on MacOS	3m 19s
Bazel	1m 24s
Bazel with async export	9m 9s
Bazel tsan config	1m 55s
Bazel valgrind	1m 36s
Bazel with external abseil	8m 50s
Benchmark	1m 0s
CMake test (build shared libraries with otlp-exporter and static gRPC)	14m 3s
Copyright	5s
Format	23s
Plugin -> CMake	54s
CMake -> exporter proto	11m 57s
CMake -> exporter proto (Build as DLL)	12m 20s
Code coverage	11m 13s
DocFX check	1m 5s
markdown-lint	7s
misspell	4s
Bazel Windows	20m 22s
Plugin -> CMake Windows	7m 7s
CMake (With async export) -> exporter proto	11m 40s
	4h 54m 4s

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