Polygon Segmentation Loading Time

**Describe the bug**
After Labeling Brush and Polygon, the loading time in tasks is huge, could take upto minutes sometimes.

**To Reproduce**
Steps to reproduce the behavior:

1. Label an image with Polygon or Brush segmentation, submit
2. Go to Tasks and try to load the image
3. You will observe that it takes a huge time to load (2-3 minutes sometimes)

**Expected behavior**
Should Load quickly

Environment (please complete the following information):**Environment (please complete the following information):**
- OS: Ubuntu
- Label Studio Version 1.7.2

**Additional context**
According to the issue #476, it should be fixed with [version 1.3.0 release](https://github.com/heartexlabs/label-studio/releases/tag/v1.3.0), however, I'm getting the same behaviour using version 1.7.2. I am using images of approximately 1500x1500 (around 5 MB) with segmentation polygons. When attempting to open these pre-labeled images, which have a relatively high number of polygons per image (it's about buildings footprint segmentation), it takes too long to open. Additionally, the user experience suffers when transitioning from one image to the next, zooming, and so on. The client-side web browser begins to consume high CPU resources.