Improve gui app disposal handling and close all network connections

[Frizi]

Pull Request Description

Fixes #8964

All GUI network connections are now closed after the application is unmounted.

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed, the GUI was tested when built using ./run ide build.

[vitvakatu]

What this change is about?

[Frizi]

Removed a component that no longer exists from stories. Just something I noticed when debugging.