Notification channels: severity => tag

Rename the user-facing parts of the notification channels.

Signed-off-by: mueller-ma <[email protected]>

mobile/src/main/res/values/strings.xml

@@ -348,8 +348,8 @@
     <string name="notification_channel_messages_default_severity">Default</string>
     <string name="notification_channel_messages_default_severity_description">Notifications sent by the server with no defined severity</string>
     <string name="notification_channel_group_messages">Messages</string>
-    <string name="notification_channel_severity_value">Severity \'%1$s\'</string>
-    <string name="notification_channel_severity_value_description">Notifications sent by the server with severity \'%1$s\'</string>
+    <string name="notification_channel_severity_value">Tag \'%1$s\'</string>
+    <string name="notification_channel_severity_value_description">Notifications sent by the server with tag \'%1$s\'</string>
     <plurals name="summary_notification_text">
         <item quantity="one">%d new notification</item>
         <item quantity="other">%d new notifications</item>