Close dropdowns

[kazcw]

Pull Request Description

Fixes #7562. Close a dropdown when:

• A click outside the dropdown occurs
• Esc is pressed
• Any other Interaction is started (i.e. using a shortcut)

Important Notes

• Simplifies Interaction API and uses it for closing/canceling CB as well as dropdowns.
• Adjusted some event handlers so that handled clicks don't also register as GraphEditor background clicks.
• Introduces a CSS approach to prevent unwanted text-selections; we were doing it with JS until my previous PR, and the JS solution was breaking things.

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.

[farmaazon]

Why this change? I deliberately changed it to click once.

[kazcw]

I was preventing some user actions triggering multiple handlers, but we can do that some other way. Fixing it isn't needed for this PR and it doesn't currently cause any observed problems.