Use %d instead of 1 in plurals strings (#967)

> Always include %d in "one" because translators will need to use
> %d for languages where "one" doesn't mean 1 (as explained above)

from https://developer.android.com/guide/topics/resources/string-resource#Plurals

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

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

@@ -9,7 +9,7 @@
     <string name="notification_channel_severity_value">Severity \'%1$s\'</string>
 
     <plurals name="summary_notification_text">
-        <item quantity="one">1 new notification</item>
+        <item quantity="one">%d new notification</item>
         <item quantity="other">%d new notifications</item>
     </plurals>
 </resources>