[NET11.0][Editor] Implemented Completed command

[NirmalKumarYuvaraj]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Description of Change

This pull request adds new command support to the Editor control, allowing developers to bind an ICommand that will be executed when the editor's text is completed (e.g., when the user presses the return key). It introduces new bindable properties for the command and its parameter, updates the completion logic to execute the command, and adds unit tests to ensure the new functionality works as expected.

New Editor Command Support:

• Added two new bindable properties to Editor: ReturnCommand (of type ICommand) and ReturnCommandParameter (of type object). These allow developers to bind a command and an optional parameter that will be executed when the editor completes input. [1] [2]
• Updated the SendCompleted method in Editor to execute the bound ReturnCommand (with its parameter) if it is set, the editor is enabled, and the command can execute. The original Completed event still fires as before.

Public API and Platform Support:

• Registered the new properties and accessors in the public API files for all supported platforms, ensuring the new command functionality is available and discoverable in the public API surface. [1] [2] [3] [4] [5] [6] [7]

Unit Testing:

• Added comprehensive unit tests for the new command functionality, including tests for command execution, command not executing when the editor is disabled, command not executing when CanExecute returns false, and ensuring both the Completed event and the command fire when appropriate. [1] [2]

Reference: https://github.com/dotnet/maui/blob/main/src/Controls/src/Core/Entry/Entry.cs

Issues Fixed

Fixes #7775