Undo Feature for Task Deletion and Completion

[its-me-abhishek]

Description

• Added a new undo feature for task deletion and completion, replacing the old alert dialog with a more user-friendly Snackbar. - The Snackbar includes an "Undo" button, allowing users to revert the task status to the previous state.
• Implemented an undo feature for task deletion and completion using Snackbars.
• Updated the UI to show a Snackbar with an "Undo" button when a task is deleted or completed.
• Revert the task status to the previous state if the user presses "Undo."

Fixes #296

Screenshots

undo-feat.mp4

Checklist

• Tests have been added or updated to cover the changes
• Documentation has been updated to reflect the changes
• Code follows the established coding style guidelines
• All tests are passing

[Pavel401]

LGTM