chore: Fix to work with sized STL string

Author: cwahn

example/efp_logger_example.cpp

@@ -34,7 +34,7 @@ int main() {
     // const auto a_1000 = std::string(1000, 'a');
     // info("This is a info message with a 1000 char string: {}", a_1000);
     // info("Does it support Korean? {}", "한글도 되나요?");
-    info("This is a info message with a empty string: {}", std::string(""));
+    // info("This is a info message with a empty string: {}", std::string(""));
 
     return 0;
 }

include/efp/logger.hpp

@@ -236,7 +236,10 @@ namespace efp {
                                                       : stl_string_head_capacity);
 
                             // Extracting the remaining parts of the string if necessary
-                            size_t remaining_length = arg.length - stl_string_head_capacity;
+                            size_t remaining_length = arg.length > stl_string_head_capacity
+                                                          ? arg.length - stl_string_head_capacity
+                                                          : 0;
+
                             while (remaining_length > 0) {
                                 _read_buffer->pop_front().match(
                                     [&](const StlStringData& d) {