e2e tests for collapsing and entering nodes

[vitvakatu]

Pull Request Description

Related to #8518

These tests already caught one regression in nav breadcrumbs: #8756

It also provides API for mocking expression updates for arbitrary nodes on the screen. The implementation is a bit convoluted and includes setting a callback on window, but it looks like the only possible solution given our architecture and playwright restrictions.

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.