Make detector_type field case-insensitive

[topguns837]

Environment 🖥️

• OS Version: Ubuntu 22/Docker

• Python Version: 3.10

• Do you have a dedicated GPU ? Yes

• NVIDIA Driver Version : 535

• CUDA Version : 11.8

• Are you running this project natively or using Docker ? Docker

• Is the issue present in the main branch or any of the development branch ? main

The field `detector_type` in the `params.yaml` file inside the `object_detection` package is case-sensitive

Description 📖

• Expected behavior: The package should for inputs YOLOV5/YOLOv5 or any combination of cases
• Actual behavior: Getting error : YOLOV5 Detector specified in config was not found. Check the Detectors dir for available detectors."

Steps to reproduce 👀

1. Type in YOLOV5 in detector_type field inside params.yaml
2. Build the package
3. Run ros2 launch object_detection object_detection.launch.py