Update deprecated JxBrowser link in Flutter JetBrains plugin documentation

[dmytro-kashcheiev]

The Flutter JetBrains Plugin documentation currently includes a deprecated link to the JxBrowser library.

This outdated link may lead to confusion and prevent users from accessing the most current compliance information and source code available.

Current Link: https://cloud.teamdev.com/downloads/jxbrowser/7.10/jxbrowser-7.10-relink.zip

Suggested Link: Please replace it with the following updated link to ensure users have access to the correct information regarding LGPL compliance and source code: https://teamdev.com/jxbrowser/lgpl-compliance/#source-code.

[jwren]

This landed with #7289