Added IUIDropDownButton and improve Json > Table UI

[veler]

Pull request type

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• Bugfix
• New feature or enhancement
• UI change (please include screenshot!)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
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What is the current behavior?

We just added a JSON > Table converter tool to DevToys 2.0. See #1003.
The UI could be improved using a Drop Down Button, which isn't available in our API yet.

Issue Number: #1005

What is the new behavior?

1. Added IUIDropDownButton.
2. Updated JSON > Table tool with a drop down button on top of the Data Grid that allows to copy or save the grid as CSV.
3. Did some refactoring
4. Added StepChanged event to IUINumberInput (seems like it got forgotten)

Other information

Before:

After:

Quality check

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• Did you follow the code style guideline as described in CONTRIBUTING.md
• Did you build the app and test your changes?
• Did you check for accessibility? On Windows, you can use Accessibility Insights for this.
• Did you verify that the change work in Release build configuration
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• If necessary and if possible, did you verify your changes on:
  • Windows
  • macOS (DevToys 2.0)
  • Linux (DevToys 2.0)

[veler]

Hi @sakana280, here is my suggested change to JSON > Table using Drop Down Button. What do you think? 😊

[sakana280]

Nice work! The target formats feel more natural as options in the dropdowns than as a tool-wide setting.