Shabbat mode toggle

[joshbrand]

Is your feature request related to a problem? Please describe.
There is a feature available for certain models that is a Shabbat mode -- it is normally enabled on a fixed schedule, or manually toggled via the app or holding a combination of buttons on the control panel

Describe the solution you'd like
A new toggle to appear to manually enable Shabbat mode so I can use this feature for more advanced automations

Describe alternatives you've considered
I took a wild stab at this, but am new to HA development

Additional context
#297 previously mentioned this, but didn't have "SabbathMode" in refState but it is showing in my diagnostics now:

              "refState": {
                "dispenserCapacity": 255.0,
                "dispenserUnit": "IGNORE",
                "freezerTemp": 7.0,
                "sabbathMode": "OFF",

here's the full diagnostic
config_entry-smartthinq_sensors-2ff7d668163b81a2aa96b928242c63f5.json