fix #406: Added the service for canceling the ringing sound

[wellorbetter]

Added the service for canceling the ringing sound & adapted onStartCommand for the service that cancels the ringing sound.

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Added part to stop ongoing service when clock is deleted.
• Adapted onStartCommand to handle cases where the alarm has been deleted, causing getAlarmWithId to return null.

Tests performed

• Tested stopping alarms after they were deleted.

Closes the following issue(s)

• Closes Not possible to stop an alarm that was deleted #406

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• I understand every change in this pull request.

[wellorbetter]

Added a service to stop the alarm when it is ringing, and also adapted the corresponding onStartCommand logic so that it can enter the stopActiveAlarm state. This is because after deleting this alarm, the applicationContext.dbHelper.getAlarmWithId would result in newAlarm being null.