Modified icons of binary sensors: gas, problem, safety, smoke

[kukulich]

Breaking change

Proposed change

Modified icons of binary sensors: gas, problem, safety, smoke
Icons are consistent (both icons are circles now) and circles are probably better because shield is often used for alarm.

We may also use mdi-check-circle-outline for "off" state to make better visual difference between "on" and "off" states.

Updated version of #6824 because there's no response.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

[koying]

Sorry if it's not the proper place, but this brings a small issue of icon usage consistency.
I don't have any issue with this change as such, but now, the "checkmark" icon is used both for "off" state for gas, problem, safety, smoke and "on" state for unknown device classes like the updater.

eg:

Here, a checkmark both means "Ok, no action" (Meteo Alarm) and "Attention, action required" (Updater).

A bit confusing, so maybe adjusting the "default" binary sensor icons might be desirable.

Thanks