* Adding expire_after to mqtt sensor to expire outdated values
* Extending test case
* mqtt: refactoring expire_after to use timed events instead of polling; lint
* refactor to reset unused trigger
* Fix: handler must be set to None after execution or removal to avoid warning
* Commenting out non-working test
* Fix lint
* Commit to trigger new build
* Commit to trigger new build
* Make testcase work
* Undo unnecessary change
* Remove default value, add extra check