Add and trigger onReady API for SMS over IMS

Test: manual test that normal code path is fine since this code path is
not yet exercisable.
BUG=69846044
Change-Id: Id56b04eea65ee06953cc819bab07b2659da2738c
diff --git a/src/java/com/android/ims/ImsManager.java b/src/java/com/android/ims/ImsManager.java
index d8ada6f..e86bfde 100644
--- a/src/java/com/android/ims/ImsManager.java
+++ b/src/java/com/android/ims/ImsManager.java
@@ -2353,6 +2353,15 @@
         }
     }
 
+    public void onSmsReady() throws ImsException{
+        try {
+            mImsServiceProxy.onSmsReady();
+        } catch (RemoteException e) {
+            throw new ImsException("onSmsReady()", e,
+                    ImsReasonInfo.CODE_LOCAL_IMS_SERVICE_DOWN);
+        }
+    }
+
     public void addRegistrationCallback(ImsRegistrationImplBase.Callback callback) {
         // TODO: implement (coming in ag/3472519)
     }