HardSwish is not supported by CANN backend

[WanliZhong]

System Information

OpenCV python version: 4.8.0.74
Operating System / Platform: Ubuntu 20.04
Python version: 3.9.6

Detailed description

When try to run PaddlePaddle OCR v3 DB on CANN backend, the warning shows that we don't support HardSwish layer.
model file: https://github.com/opencv/opencv_zoo/pull/180/files#diff-aefc798acfa87f717937f410d0cf692b125224f068d3052ece78343f0c0f6b11

[ WARN:0@0.310] global net_cann.cpp:120 initBackend DNN/CANN: layer (name=onnx_node!p2o.HardSwish.0, type=HardSwish) is not supported by CANN backend. 
Going back to default backend on CPU target

Steps to reproduce

just read this model and set backend to CANN, then forward.

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)