fix: clang warning about deprecated sprintf usage (XRPLF#4747)

Resolves a warning that was emitted from the clang compiler. Switches
usage of the sprintf function to the recommended snprintf function.

Warning was observed in Apple clang version 15.0.0 (clang-1500.0.40.1).

Fix XRPLF#4569

src/ripple/json/impl/json_reader.cpp

@@ -922,10 +922,8 @@ Reader::getLocationLineAndColumn(Location location) const
 {
     int line, column;
     getLocationLineAndColumn(location, line, column);
-    constexpr std::size_t n = 18 + 16 + 16 + 1;
-    char buffer[n];
-    snprintf(buffer, n, "Line %d, Column %d", line, column);
-    return buffer;
+    return "Line " + std::to_string(line) + ", Column " +
+        std::to_string(column);
 }
 
 std::string