(settings): update dormant session alert description

Author: Radosław Wieczorek

res/values/strings.xml

@@ -278,6 +278,6 @@
   <string name="other">Other</string>
   <string name="view_note">\"View Note\"</string>
   <string name="streaming_alert">Dormant stream alert</string>
-  <string name="streaming_alert_summary">Check to receive an email when active fixed sessions go dormant for >60 minutes</string>
+  <string name="streaming_alert_summary">Check to receive an email when active fixed sessions go dormant for >30 minutes</string>
     <string name="heat_map_density_warning">CrowdmMap grid cell size must be a number 1-40</string>
 </resources>