Removed some non-translatable strings and just hardcoded them in the code, like it's being done for other string separators. This also deduplicates some code by using Localization.
Used some Kotlin feature to reduce code.
Do not open the setting for a specific notification channel (Settings.ACTION_CHANNEL_NOTIFICATION_SETTINGS), but the settings for all notifications by the app (Settings.ACTION_APP_NOTIFICATION_SETTINGS)