Fix redundant imports when selecting options from the dropdown widget

[vitvakatu]

Pull Request Description

Fixes #6816.

The code for adding imports for dropdown widgets was unified with CB. The code was moved from the searcher controller to the graph controller.

Also, I changed the signature for a few lookup_* methods of the suggestion database, because I have always found it weird that they return Option instead of Result. They now work nicely with the surrounding code.

2023-06-15.17-57-13.mp4

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,
  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.

[kazcw]

Looks good. A few nits.

[xvcgreg]

@vitvakatu What's the status here?

[wdanilo]

Nice solution!

[vitvakatu]

@xvcgreg QA requested, @Frizi will report results.

[Frizi]

QA Status: 💚

Looks great, barely anything now gets imported when from Standard.Base import all is present. And when I manually remove that import, the appropriate gets correctly imported on demand.