ISO 8601 Support In Date Converter

[yui10]

Pull request type

Please check the type of change your PR introduces:

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

Issue Number: DevToys-app/DevToys#1229

What is the new behavior?

• Conversion by ISO 8601 is now possible

Other information

Any format that can be converted with DateTimeOffset.TryParse is available.
https://learn.microsoft.com/en-us/dotnet/api/system.datetimeoffset.tryparse?view=net-8.0

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
• Did you verify that all unit tests pass
• If necessary and if possible, did you verify your changes on:
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[veler]

Thank you for this! I will try to review it ASAP