Allow climate card to have temperature control buttons without mode selector

[Cretezy]

In 2025.3, the climate control buttons (-/+) only show up when enabling the "Climate HVAC modes" feature.

With feature on:

With feature off (this doesn't much sense except as a display):

I would like to hide the large heating button, as it's the only option for baseboard thermostats.

In the "Climate HVAC modes" configuration, I would either like:

• The ability to have a "None" mode which hides the button
• The ability to hide the button if customizing the modes when no modes are selected

[Cretezy]

This is something I can implement if it's agreed on. I think having a "None" style would be the best option.

[karwosts]

I kind of think this is just an unintended bug. The buttons used to be visible in 2025.2 without feature and I'm not seeing any change that explicitly tried to remove them.

[karwosts]

Should be fixed by #24634, but thanks anyway for volunteering and bringing attention to it.

[Cretezy]

Thanks!