Remove unused string from BlockedNumberProvider resources.

BUG: 26232372

Change-Id: Ib0f1c486f72de6a905aa663bb9df70331e087751
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 860e115..46b7af6 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -19,7 +19,4 @@
     <!-- This is the label for the application that stores blocked phone numbers [CHAR LIMIT=NONE] -->
     <string name="app_label">Blocked Numbers Storage</string>
 
-    <!-- This is the label for the provider that stores blocked phone numbers [CHAR LIMIT=NONE] -->
-    <string name="provider_label">Blocked Numbers</string>
-
 </resources>