fix(bytetrack): No need to throw exception when idx is out of range

Since ColorMapper just returns a unique color to the caller,
we simply use modulo to get a valid color index.
In such a way there is no need to check the index validity and throw
a runtime exception.

Signed-off-by: chtseng <chtseng@itri.org.tw>

perception/bytetrack/include/bytetrack/bytetrack_visualizer_node.hpp

@@ -31,7 +31,6 @@
 
 #include <algorithm>
 #include <memory>
-#include <stdexcept>
 #include <string>
 #include <vector>
 
@@ -54,10 +53,7 @@ class ColorMapper
 
   cv::Scalar operator()(size_t idx)
   {
-    if (kColorNum <= idx) {
-      throw std::runtime_error("idx should be between [0, 255]");
-    }
-    return color_table_.at<cv::Vec3b>(0, idx);
+    return color_table_.at<cv::Vec3b>(0, idx % kColorNum);
   }
 
 protected: