Fix #1398: Delete specific task instance in RoutineBuilder by checking

[shabnam311]

Description

This PR resolves #1398, where clicking the delete button on a specific scheduled task instance in the Routine Builder was mistakenly deleting all instances of that task on the same day.

Changes Made

• Modified WeeklyGrid.jsx to pass the task.startTime into the onDeleteTask event handler, rather than just the taskId and day.
• Updated the removeScheduledTask function in RoutineBuilder.jsx to accept startTime and include it in the .filter() logic.
• The removeScheduledTask function now successfully targets and deletes only the specific task occurring at the precise time slot clicked by the user.

Testing

• Dragged a "Read" task to Monday 9:00 AM and Monday 10:00 AM.
• Clicked delete on the 10:00 AM task.
• Verified that only the 10:00 AM task was removed, while the 9:00 AM task correctly remained in the grid.