refactor(pdf_extract_kit): update model config and weight paths for UniMERNet-0.2.0

Update the paths to model weights and configuration files for the UniMERNet architecture
in both the demo.yaml and model_configs.yaml files. Adjust the mfr_model_init function toreflect the new weight and configuration paths. The changes include specifying more detailed
paths to the unimernet_base directory and changing the weight file extension to .pth.

setup.py

@@ -36,7 +36,7 @@ if __name__ == '__main__':
                      "paddlepaddle==3.0.0b1;platform_system=='Linux'",
                      "paddlepaddle==2.6.1;platform_system=='Windows' or platform_system=='Darwin'",
                      ],
-            "full": ["unimernet==0.1.6",  # 0.1.6版本大幅裁剪依赖包范围，推荐使用此版本
+            "full": ["unimernet==0.2.0",  # unimernet升级0.2.0
                      "matplotlib<=3.9.0;platform_system=='Windows'",  # 3.9.1及之后不提供windows的预编译包，避免一些没有编译环境的windows设备安装失败
                      "matplotlib;platform_system=='Linux' or platform_system=='Darwin'",  # linux 和 macos 不应限制matplotlib的最高版本，以避免无法更新导致的一些bug
                      "ultralytics",  # yolov8,公式检测