Fix study not found on windows when using simulator API (#2481)

Fix an issue when using simulator API on windows where windows path with
drive letter were unsuported

src/libs/antares/file-tree-study-loader/FileTreeStudyLoader.cpp

@@ -29,7 +29,7 @@
 namespace Antares
 {
 FileTreeStudyLoader::FileTreeStudyLoader(std::filesystem::path study_path):
-    study_path_{std::move(study_path)}
+    study_path_{std::move(study_path.string())}
 {
 }
 
@@ -38,10 +38,7 @@ std::unique_ptr<Antares::Data::Study> FileTreeStudyLoader::load() const
     using namespace std::literals::string_literals;
     Antares::Solver::Application application;
     constexpr unsigned int argc = 3;
-    // On Windows, std::filesystem::path::value_type is wchar_t
-    std::array<const char*, argc> argv{"",
-                                       reinterpret_cast<const char*>(study_path_.c_str()),
-                                       "--parallel"};
+    std::array<const char*, argc> argv{"", study_path_.c_str(), "--parallel"};
     application.prepare(argc, argv.data());
 
     return application.acquireStudy();

src/libs/antares/file-tree-study-loader/include/antares/file-tree-study-loader/FileTreeStudyLoader.h

@@ -58,6 +58,6 @@ class FileTreeStudyLoader: public IStudyLoader
     [[nodiscard]] std::unique_ptr<Antares::Data::Study> load() const override;
 
 private:
-    std::filesystem::path study_path_;
+    std::string study_path_;
 };
 } // namespace Antares