feat: Support PasswordBox on Skia

[Youssef1313]

GitHub Issue (If applicable): closes #6396, closes #5767

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

No support for PasswordBox on Skia GTK

What is the new behavior?

Supported

PR Checklist

Please check if your PR fulfills the following requirements:

• Docs have been added/updated which fit documentation template (for bug fixes / features)
• 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

Internal Issue (If applicable):

[gitpod-io]

[davidjohnoliver]

@Youssef1313 There was a regression reported on Discord, I'm guessing it's related to this PR.

I can repro with the following XAML in a new app using latest Uno.UI:

	<StackPanel Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" Margin="30">
		<Button Content="dummy" />
		<TextBox Text="should be a normal textbox"/>
	</StackPanel>

On Skia.Gtk the TextBox looks like a PasswordBox. If I focus it the text appears normally, but if I remove focus again by clicking the button then the text is obscured.

Could you take a look into it?

The report on Discord:

I find out that in version 3.10.0-dev.396 textbox working like passwordbox on SKIA. On dev.385 everything fine (it just doesn't work).

[Youssef1313]

The problem should probably be here. I'll take a look to confirm and fix. Sorry for introducing such a regression :(

[davidjohnoliver]

No worries, happens to everybody. :)

For my part, I somehow did not even notice this line when I reviewed the PR.

[Youssef1313]

I'm noticing other issues with TextBox on Gtk when running Samples App:

• UI hangs a little bit while typing (especially with fast typing).
• Can't click middle of existing text to being editing
• Trying to select text doesn't work (both through mouse dragging and CTRL+A)

I reverted my commits locally to make sure these issues are unrelated to my changes and indeed they're unrelated.

I also found that my implementation doesn't only break TextBox, but breaks PasswordBox itself when RevealMode is set programmatically (not through the reveal button). But I wasn't able to completely fix that.