feat(NumericUpDown): TextAlignment

[workgroupengineering]

What does the pull request do?

Add TextAlignment property to NumericUpDown

What is the current behavior?

It doesn't have the TextAlignment property. To change the alignment you need to create a style selector like this:

    <Style Selector="NumericUpDown /template/ TextBox#PART_TextBox">
      <Setter Property="TextAlignment" Value="Right"/>
    </Style>

This solution has the disadvantage of strictly depending on the theme used.

What is the updated/expected behavior with this PR?

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/Documentation with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

Fixes #12367

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0038213-beta. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]