Add nullability annotations in accordance with the council

Bug: 126702532
Test: atest FrameworksTelephonyTests
Change-Id: I7c3707d7599ec0e2a1d1ec2e70588765aea5d069
diff --git a/api/system-current.txt b/api/system-current.txt
index 1f58de8..cd98fe2 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -7400,7 +7400,7 @@
   public static class ProvisioningManager.Callback {
     ctor public ProvisioningManager.Callback();
     method public void onProvisioningIntChanged(int, int);
-    method public void onProvisioningStringChanged(int, String);
+    method public void onProvisioningStringChanged(int, @NonNull String);
   }
 
 }
diff --git a/telephony/java/android/telephony/ims/ProvisioningManager.java b/telephony/java/android/telephony/ims/ProvisioningManager.java
index 204891b..cdfc955 100644
--- a/telephony/java/android/telephony/ims/ProvisioningManager.java
+++ b/telephony/java/android/telephony/ims/ProvisioningManager.java
@@ -153,7 +153,7 @@
          * @param item the IMS provisioning key constant, as defined by the OEM.
          * @param value the new String value of the IMS configuration constant.
          */
-        public void onProvisioningStringChanged(int item, String value) {
+        public void onProvisioningStringChanged(int item, @NonNull String value) {
             // Base Implementation
         }