Removed specific MSVC settings when installing (#17285)

When installing protobuf, it creates a different directory for CMake's config files when compiling with MSVC.

![protobuf-on-windows](https://github.com/protocolbuffers/protobuf/assets/50274155/b0f5e1fa-dcb8-4c01-8118-7c6c651cda37)
_gRPC build on Windows_

![protobuf-on-linux](https://github.com/protocolbuffers/protobuf/assets/50274155/1370b476-89e7-42a0-857d-73cdcbae4f23)
_gRPC build on Linux and macOS_

This is problematic because it requires conditionally setting its `protobuf_DIR` for different platforms:

```cmake
if(MSVC)
    set(Protobuf_DIR "${PROTOBUF_PREFIX}/cmake")
else()
    set(Protobuf_DIR "${PROTOBUF_PREFIX}/lib/cmake/protobuf")
endif()
```

[The original commit that made this](7d79458) based its choice on CMake's version 3.4, which not only is deprecated but is also based on a CMake version [less than the one defined in the master file](https://github.com/protocolbuffers/protobuf/blob/main/CMakeLists.txt#L3). Since then, CMake changed its behaviour, making this distinction unnecessary.

Closes #17285

COPYBARA_INTEGRATE_REVIEW=#17285 from EduMenges:main a6f2e37
PiperOrigin-RevId: 650455064

cmake/install.cmake

@@ -122,15 +122,9 @@ set(_install_cmakedir_desc "Directory relative to CMAKE_INSTALL to install the c
 set(_build_cmakedir_desc "Directory relative to CMAKE_CURRENT_BINARY_DIR for cmake configuration files")
 set(_exampledir_desc "Directory relative to CMAKE_INSTALL_DATA to install examples")
 set(_protobuf_subdir_desc "Subdirectory in which to install cmake configuration files")
-if(NOT MSVC)
-  set(protobuf_CMAKE_SUBDIR "cmake/protobuf" CACHE STRING "${_protobuf_subdir_desc}")
-  set(CMAKE_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/${protobuf_CMAKE_SUBDIR}" CACHE STRING "${_install_cmakedir_desc}")
-  set(CMAKE_INSTALL_EXAMPLEDIR "${CMAKE_INSTALL_DATADIR}/protobuf/examples" CACHE STRING "${_exampledir_desc}")
-else()
-  set(protobuf_CMAKE_SUBDIR "cmake" CACHE STRING "${_protobuf_subdir_desc}")
-  set(CMAKE_INSTALL_CMAKEDIR "cmake" CACHE STRING "${_cmakedir_desc}")
-  set(CMAKE_INSTALL_EXAMPLEDIR "examples" CACHE STRING "${_exampledir_desc}")
-endif()
+set(protobuf_CMAKE_SUBDIR "cmake/protobuf" CACHE STRING "${_protobuf_subdir_desc}")
+set(CMAKE_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/${protobuf_CMAKE_SUBDIR}" CACHE STRING "${_install_cmakedir_desc}")
+set(CMAKE_INSTALL_EXAMPLEDIR "${CMAKE_INSTALL_DATADIR}/protobuf/examples" CACHE STRING "${_exampledir_desc}")
 set(CMAKE_BUILD_CMAKEDIR "${CMAKE_CURRENT_BINARY_DIR}/${protobuf_CMAKE_SUBDIR}" CACHE STRING "${_build_cmakedir_desc}")
 mark_as_advanced(protobuf_CMAKE_SUBDIR)
 mark_as_advanced(CMAKE_BUILD_CMAKEDIR)