Add string for number of hotspot connected devices

Add it in settingslib so both systemui and settings could use it.

Bug: 3485717
Test: Build
Change-Id: I692d923f1881440c16612779c0a9fe56ac491029
diff --git a/packages/SettingsLib/res/values/strings.xml b/packages/SettingsLib/res/values/strings.xml
index b13de2e..f6541bb 100644
--- a/packages/SettingsLib/res/values/strings.xml
+++ b/packages/SettingsLib/res/values/strings.xml
@@ -1015,4 +1015,10 @@
     <!-- About phone, status item value if the actual value is not available. -->
     <string name="status_unavailable">Unavailable</string>
 
+    <!-- Summary to show how many devices are connected in wifi hotspot [CHAR LIMIT=NONE] -->
+    <plurals name="wifi_tether_connected_summary">
+        <item quantity="one">%1$d device connected</item>
+        <item quantity="other">%1$d devices connected</item>
+    </plurals>
+
 </resources>