Settings page is unaware of license changes after activation

[Brugman]

Hi. I've included class-plugin-updater.php in my plugin, but I'm refactoring class-settings-page.php to fit me better. Regardless, even in its original form, I think class-settings-page.php is missing some important functionality.

Checking if a stored license is valid, is done with $license_message->data->activated, which comes from the example_plugin_license_message option. That option is only created/updated in activate_license. That function is only called inside handle_license_activation and only if a new license key is set. And that function is only run when the update_option_example_plugin_settings_option_name hook triggers, which has to do with submitting a form.

Here's a scenario:
The user installs the plugin, enters their license, it gets checked, it's valid, the response saying it's valid gets stored in example_plugin_license_message, the plugin continues to work.
13 months later, the license is expired. I think the settings page will still say that it's valid. Unless you remove the license and re-enter the same license. Then the check will be done again, and mess up their advantageous bug.

I think we need to add some code to recheck the license every X days.

Kinda related but unrelated: Why is the settings page code using the example_plugin_license_message option, but the updater code does not? The updater is completely disconnected and stores results in a transient. Why two methods?

Thanks.