[Backups] Fix database dump error reporting (#3175)

* [Backups] Fix database dump error reporting

* Update database_dump_service.cpp

common/file.h

@@ -25,10 +25,16 @@
 
 namespace fs = std::filesystem;
 
+struct FileContentsResult {
+	std::string contents;
+	std::string error;
+};
+
 class File {
 public:
 	static bool Exists(const std::string &name);
 	static void Makedir(const std::string& directory_name);
+	static FileContentsResult GetContents(const std::string &file_name);
 	static std::string FindEqemuConfigPath();
 	static std::string GetCwd();
 };