Store subscriber ID / IMSI into telephony database

Bug: 131916175
Test: manual
Change-Id: I64cd12a6737b7ef7fb31b851c1cbb5b7f46e6ca7
Merged-In: I64cd12a6737b7ef7fb31b851c1cbb5b7f46e6ca7
(cherry picked from commit 4e97d2c105)

telephony/java/android/telephony/SubscriptionManager.java

@@ -790,6 +790,14 @@ public class SubscriptionManager {
     @SystemApi
     public static final int PROFILE_CLASS_DEFAULT = PROFILE_CLASS_UNSET;
 
+    /**
+     * IMSI (International Mobile Subscriber Identity).
+     * <P>Type: TEXT </P>
+     * @hide
+     */
+    //TODO: add @SystemApi
+    public static final String IMSI = "imsi";
+
     /**
      * Broadcast Action: The user has changed one of the default subs related to
      * data, phone calls, or sms</p>