Fix component browser test.

[farmaazon]

Pull Request Description

One test was randomly failing - we deselected node, and expected small plus button will disappear despite the node could be still hovered by mouse.

Actually, I don't know how did it stay with us so long.

Important Notes

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,
  TypeScript,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• Unit tests have been written where possible.