utils: Use u8path to fix possible string conversion crashes on Windows

All other path operations in the code base already use u8path to ensure
that the strings provided by libobs (which will either be ASCII or
UTF-8 byte sequences) are correctly converted into UTF-16 strings.

Author: PatTheMav

src/utils/Json.cpp

@@ -178,7 +178,7 @@ json Utils::Json::ObsDataToJson(obs_data_t *d, bool includeDefault)
 
 bool Utils::Json::GetJsonFileContent(std::string fileName, json &content)
 {
-	std::ifstream f(fileName);
+	std::ifstream f(std::filesystem::u8path(fileName));
 	if (!f.is_open())
 		return false;
 
@@ -195,9 +195,11 @@ bool Utils::Json::GetJsonFileContent(std::string fileName, json &content)
 
 bool Utils::Json::SetJsonFileContent(std::string fileName, const json &content, bool makeDirs)
 {
+	auto jsonFilePath = std::filesystem::u8path(fileName);
+
 	if (makeDirs) {
+		auto p = jsonFilePath.parent_path();
 		std::error_code ec;
-		auto p = std::filesystem::path(fileName).parent_path();
 		if (!ec && !std::filesystem::exists(p, ec))
 			std::filesystem::create_directories(p, ec);
 		if (ec) {
@@ -207,7 +209,7 @@ bool Utils::Json::SetJsonFileContent(std::string fileName, const json &content,
 		}
 	}
 
-	std::ofstream f(fileName);
+	std::ofstream f(jsonFilePath);
 	if (!f.is_open()) {
 		blog(LOG_ERROR, "[Utils::Json::SetJsonFileContent] Failed to open file `%s` for writing", fileName.c_str());
 		return false;