With this commit, activities will automatically change theme between day/night if `night-mode` `termux.properties` is not set or is set to `system` without requiring app restart.
Dialog theming will be fully added in a later commit and may currently be in an inconsistent state or have crashes.
The `uiMode` has been removed from `configChanges` of `TermuxActivity`, this may cause termux app to restart if samsung DEX mode is changed, if it does, then users should report it so that it can be fixed by re-adding the value and ignoring the change inside `TermuxActivity.onConfigurationChanged()`. The docs don't state if its necessary. Check related pull request #1446.
Running `termux-reload-settings` will also restart `TermuxActivity`, the activity data should be preserved.
This will not break existing `use-black-ui` settings for users and it will automatically be converted to `night-mode` when properties are loaded from disk but a deprecation message will be logged.
This `night-mode` key can be used to set the day/night theme variant for activities used by termux app and its plugin. The user can set a string value to `true` to force use dark variant of theme, `false` to force use light variant of theme or `system` to automatically set theme based on current system settings. The default value is still `system`. The app must be restarted for changes to take effect for existing activities, including main terminal `TermuxActivity`.
This is required since "theme != night mode". In future custom theme or color support may be provided that will have both dark and night modes for the same theme.
