[Performance Issue] Slow Performance

### Prerequisites

- [X] I [searched for any existing report](https://github.com/darkreader/darkreader/issues?q=is%3Aissue) about this performance issue to avoid opening a duplicate.
- [X] I have restarted the web browser to check if that resolved this performance issue.
- [X] I can reproduce this performance issue in a new, unmodified web browser profile with Dark Reader installed as the only extension.

### Performance Issue Description

I was discovering plugins that slow down my site speed and your plugin is one of them.

### Website Address

https://giocone.com/games/

### Steps To Reproduce

1. open firefox
2. firefox developper tool
3. net
4. Click the button to start performance analysis.
5. Reload for many seconds pages. After disable/enable your plugin and reload page again many times.

### Performance Profile

https://drive.google.com/file/d/1v0tSXjVqqz6ikoReW5TJJh_7WK7OZXYO/view?usp=sharing

### Screenshots

https://imgur.com/a/ohlpJZj

### Operating System

MacOS BIg Sur version 11.7.10

### Web Browser name and version

Firefox 127.0

### Dark Reader version

Version 5.0.6

### Does this happen when Dark Reader is disabled?

No

### Does this happen in other web browsers?

Yes

### Additional Context

I've tried only on Firefox.