fix: use AlarmControlPanelState constants

[francescolf]

Also directly imports AlarmControlPanelEntity since the minimum required HA version already has this implemented.

Closes #2655

[coveralls]

Pull Request Test Coverage Report for Build 11617468899

Details

• 0 of 8 (0.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.003%) to 10.006%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
custom_components/alexa_media/alarm_control_panel.py	0	8	0.0%

Files with Coverage Reduction	New Missed Lines	%
custom_components/alexa_media/alarm_control_panel.py	1	0.0%

Totals
Change from base Build 11606799556:	-0.003%
Covered Lines:	344
Relevant Lines:	3438

---

💛 - Coveralls

[alandtse]

Please note pre commit is failing. Either run it locally and push or enable us to modify your branch so the ci can handle.