docs(CTK8): Added converters usage sample

[DevTKSS]

GitHub Issue (If applicable): closes #18669

PR Type

What kind of change does this PR introduce?

• Documentation content changes

What is the current behavior?

currently missing in Documentation

What is the new behavior?

added missing sample

PR Checklist

Please check if your PR fulfills the following requirements:

• Docs have been updated
• Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
• Validated PR Screenshots Compare Test Run results.
• Contains NO breaking changes
• Associated with an issue (GitHub or internal) and uses the automatic close keywords.
• Commits must be following the Conventional Commits specification.

Other information

Replaces PR #19086 and #18726

Internal Issue (If applicable):

[unodevops]

⚠️⚠️ The build 151745 has failed on Uno.UI - docs.

[unodevops]

⚠️⚠️ The build 151747 has failed on Uno.UI - docs.

[unodevops]

🤖 Your Docs stage site is ready! Visit it here: https://unodocsprstaging.z13.web.core.windows.net/pr-19212/index.html

[DevTKSS]

On the ci outputed page, the namespaces on settingscard and the converters, the namespace using seems like not correctly formatted, maybe a line break needed?
Inspected the preview on GitHub which is showing the same, but the raw code is not showing anything indicating that issue. Would need someone to check and maybe see that missing chars

[DevTKSS]

@MartinZikmund moved to here, the pr history of that other branch was not clean-up able to me. The ci runned through now only problem is with the using mentioned on last comment here. I do not see why this is happening, only thing i did remove has been spaces at the line ending which would have leaded to markdown linting issues...