Update CMAKE_LANG_FLAGS_CONFIG_INIT appending in toolchain to avoid f…

…lag repetition (openvinotoolkit#27352)

### Details:
-Currently, when using this toolchain and print the following flags in
[CMakeLists](https://github.com/openvinotoolkit/openvino/blob/master/CMakeLists.txt)
```
CMAKE_CXX_FLAGS_RELEASE in OV CMakeLists.txt::: /MT /MT /O2 /Ob2 /DNDEBUG /Zi /FS /Zf /ZH:SHA_256 /guard:cf /Qspectre
CMAKE_C_FLAGS_RELEASE in OV CMakeLists.txt::: /MT /MT /O2 /Ob2 /DNDEBUG /Zi /FS /Zf /ZH:SHA_256 /guard:cf /Qspectre
CMAKE_CXX_FLAGS_RELEASE_INIT in OV CMakeLists.txt::: /MT /MT /O2 /Ob2 /DNDEBUG
CMAKE_C_FLAGS_RELEASE_INIT in OV CMakeLists.txt::: /MT /MT /O2 /Ob2 /DNDEBUG
```
So there is repetition of `/MT` in flags.
The change in this PR will fix this problem. The flags will be:

```
CMAKE_CXX_FLAGS_RELEASE in OV CMakeLists.txt::: /MT /O2 /Ob2 /DNDEBUG /Zi /FS /Zf /ZH:SHA_256 /guard:cf /Qspectre
CMAKE_C_FLAGS_RELEASE in OV CMakeLists.txt::: /MT /O2 /Ob2 /DNDEBUG /Zi /FS /Zf /ZH:SHA_256 /guard:cf /Qspectre
CMAKE_CXX_FLAGS_RELEASE_INIT in OV CMakeLists.txt::: /MT /O2 /Ob2 /DNDEBUG
CMAKE_C_FLAGS_RELEASE_INIT in OV CMakeLists.txt::: /MT /O2 /Ob2 /DNDEBUG
```

### Tickets:
 - *152927*

Signed-off-by: Kang Wenjing <[email protected]>

cmake/toolchains/mt.runtime.win32.toolchain.cmake

@@ -28,9 +28,9 @@ if(use_static_runtime)
             set(flag_var "CMAKE_${lang}_FLAGS${build_type}_INIT")
             string(REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
             if (build_type STREQUAL "_DEBUG")
-                set(${flag_var} "${${flag_var}} /MTd")
+                set(${flag_var} "/MTd")
             else()
-                set(${flag_var} "${${flag_var}} /MT")
+                set(${flag_var} "/MT")
             endif()
         endforeach()
     endforeach()