Add FrontEndManager::register_front_end(fs::path) & Refactor validate_path (#33296)

### Details:
 - Add `FrontEndManager::register_front_end(fs::path)`
 - Update tests to use `fs::path`, add one test for `std::string`

### Tickets:
 - [CVS-178343](https://jira.devtools.intel.com/browse/CVS-178343)

Author: almilosz

src/core/tests/frontend/frontend_manager.cpp

@@ -15,9 +15,9 @@
 
 using namespace ov::frontend;
 
-static std::string mock_fe_path() {
-    static auto lib_name = std::string(FRONTEND_LIB_PREFIX) + "mock1" + std::string(FRONTEND_LIB_SUFFIX);
-    return ov::util::path_join({ov::test::utils::getExecutableDirectory(), lib_name}).string();
+static std::filesystem::path mock_fe_path() {
+    return ov::test::utils::to_fs_path(ov::test::utils::getExecutableDirectory()) /
+           std::filesystem::path(FRONTEND_LIB_PREFIX).concat("mock1").concat(FRONTEND_LIB_SUFFIX);
 }
 
 TEST(FrontEndManagerTest, testAvailableFrontEnds) {
@@ -42,7 +42,7 @@ TEST(FrontEndManagerTest, testAvailableFrontEnds) {
 
 TEST(FrontEndManagerTest, testFailRegisterFEByWrongPath) {
     FrontEndManager fem;
-    ASSERT_THROW(fem.register_front_end("mock1", mock_fe_path() + "_wrong"), ov::frontend::GeneralFailure);
+    ASSERT_THROW(fem.register_front_end("mock1", mock_fe_path().concat("_wrong")), ov::frontend::GeneralFailure);
 }
 
 TEST(FrontEndManagerTest, testMockPluginFrontEnd) {

src/frontends/common/include/openvino/frontend/frontend.hpp

@@ -167,10 +167,7 @@ class FRONTEND_API FrontEnd {
 
     virtual InputModel::Ptr load_impl(const std::vector<ov::Any>& variants) const;
 
-    void validate_path(const std::string& path) const;
-#if defined(OPENVINO_ENABLE_UNICODE_PATH_SUPPORT) && defined(_WIN32)
-    void validate_path(const std::wstring& path) const;
-#endif
+    void validate_path(const std::filesystem::path& path) const;
 
     std::vector<ov::Extension::Ptr> m_extensions;
 

src/frontends/common/include/openvino/frontend/manager.hpp

@@ -75,6 +75,7 @@ class FRONTEND_API FrontEndManager final {
     /// be created
     void register_front_end(const std::string& name, FrontEndFactory creator);
 
+    ///@{
     /// \brief Register frontend with name and factory loaded from provided library
     ///
     /// \param name Name of front end
@@ -84,6 +85,15 @@ class FRONTEND_API FrontEndManager final {
     /// to identify library full name
     void register_front_end(const std::string& name, const std::string& library_path);
 
+    void register_front_end(const std::string& name, const std::filesystem::path& library_path);
+
+    template <class Path, std::enable_if_t<std::is_constructible_v<std::string, Path>>* = nullptr>
+    void register_front_end(const std::string& name, const Path& library_path) {
+        // needed due to ambiguity between string and filesystem::path calls
+        register_front_end(name, std::string(library_path));
+    }
+    ///@}
+
 private:
     class Impl;
 

src/frontends/common/src/frontend.cpp

@@ -109,16 +109,9 @@ std::string FrontEnd::get_name() const {
     FRONTEND_RETURN_STATEMENT("Getting frontend name", m_actual->get_name();)
 }
 
-void FrontEnd::validate_path(const std::string& path) const {
+void FrontEnd::validate_path(const std::filesystem::path& path) const {
     FRONT_END_GENERAL_CHECK(util::directory_exists(path) || util::file_exists(path),
                             get_name(),
-                            ": Could not open the file: \"",
-                            path,
-                            '"');
+                            ": Could not open the file: ",
+                            path);
 }
-
-#if defined(OPENVINO_ENABLE_UNICODE_PATH_SUPPORT) && defined(_WIN32)
-void FrontEnd::validate_path(const std::wstring& path) const {
-    validate_path(ov::util::wstring_to_string(path));
-}
-#endif

src/frontends/common/src/manager.cpp

@@ -105,8 +105,8 @@ class FrontEndManager::Impl {
         m_plugins.push_back(std::move(plugin_info));
     }
 
-    void register_front_end(const std::string& name, const std::string& library_path) {
-        auto lib_path = ov::util::get_plugin_path(ov::util::make_path(library_path));
+    void register_front_end(const std::string& name, const std::filesystem::path& library_path) {
+        auto lib_path = ov::util::get_plugin_path(library_path);
         PluginInfo plugin;
         plugin.m_file_path = ov::util::path_to_string(lib_path);
         plugin.m_file_name = ov::util::path_to_string(lib_path.filename());
@@ -238,6 +238,10 @@ void FrontEndManager::register_front_end(const std::string& name, FrontEndFactor
 }
 
 void FrontEndManager::register_front_end(const std::string& name, const std::string& library_path) {
+    m_impl->register_front_end(name, ov::util::make_path(library_path));
+}
+
+void FrontEndManager::register_front_end(const std::string& name, const std::filesystem::path& library_path) {
     m_impl->register_front_end(name, library_path);
 }