Implement EntryCell VerticalTextAlignment

[jsuarezruiz]

Adds EntryCell.VerticalTextAlignment support in the compatibility handler.

Changes:

• Maps EntryCell.VerticalTextAlignment through the existing EntryCellHandler mapper.
• Adds test coverage for initial mapping and property updates. Also, added a render test.
• Updates the sample to show EntryCell vertical alignment behavior.

[Copilot]

Pull request overview

Adds support for EntryCell.VerticalTextAlignment in the Avalonia-based compatibility implementation, ensuring EntryCell text can be top/center/bottom aligned and validated via both unit and render tests.

Changes:

• Implement vertical text alignment mapping for EntryCell by wiring it into the existing Avalonia TextBox.VerticalContentAlignment behavior.
• Adjust MauiEntryCell layout so the input can stretch vertically (enabling meaningful vertical content alignment).
• Add coverage via new handler tests and a new TableView render test (plus render-test handler registration and project references), and update the ControlGallery sample.

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/Avalonia.Controls.Maui.Tests/Handlers/Cells/EntryCellHandlerTests.cs	Adds unit tests for initial mapping and runtime updates of VerticalTextAlignment.
tests/Avalonia.Controls.Maui.RenderTests/Tests/TableViewRenderTests.cs	Introduces a render test validating visual vertical alignment for EntryCells in a TableView.
tests/Avalonia.Controls.Maui.RenderTests/TestAppBuilder.cs	Registers compatibility handlers needed to render TableView/EntryCell in render tests.
tests/Avalonia.Controls.Maui.RenderTests/Avalonia.Controls.Maui.RenderTests.csproj	Adds Compatibility project reference so render tests can use compatibility handlers.
STATUS.md	Updates implementation status to mark EntryCell.VerticalTextAlignment as implemented.
src/Avalonia.Controls.Maui/Extensions/EntryExtensions.cs	Refactors vertical alignment mapping to reuse a new overload taking TextAlignment.
src/Avalonia.Controls.Maui/Extensions/EditorExtensions.cs	Reuses the shared vertical alignment mapping helper for editors.
src/Avalonia.Controls.Maui.Compatibility/Extensions/EntryCellExtensions.cs	Implements EntryCell vertical alignment mapping via the shared TextBox extension.
src/Avalonia.Controls.Maui.Compatibility/Controls/MauiTableView/MauiEntryCell.cs	Changes the input TextBox to stretch vertically to allow top/center/bottom content alignment.
samples/ControlGallery/ControlGallery/Pages/TableViewPage.xaml	Adds a sample section demonstrating EntryCell vertical text alignment.

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