Fix potential NPE in EmergencyCallbackModeExitDialog.

Ensure NPE will not crash com.android.phone process.

Test: Manual using test app provided in bug
Bug: 79995313
Change-Id: I83a5e94acdae4287e6a62558cffb586d35930b47
Merged-In: I8b899023b0977e4a8963cc536602ced4f7e43769
(cherry picked from commit 00f0c43dc4dd37d13ef614e84492783a9a6e981b)
diff --git a/src/com/android/phone/EmergencyCallbackModeExitDialog.java b/src/com/android/phone/EmergencyCallbackModeExitDialog.java
index f5509b9..07d518f 100644
--- a/src/com/android/phone/EmergencyCallbackModeExitDialog.java
+++ b/src/com/android/phone/EmergencyCallbackModeExitDialog.java
@@ -80,9 +80,11 @@
 
         mPhone = PhoneGlobals.getInstance().getPhoneInEcm();
         // Check if phone is in Emergency Callback Mode. If not, exit.
-        final boolean isInEcm = mPhone.isInEcm();
-        Log.i(TAG, "ECMModeExitDialog launched - isInEcm: " + isInEcm + " phone:" + mPhone);
-        if (mPhone == null || !isInEcm) {
+        if (mPhone == null || !mPhone.isInEcm()) {
+            if (mPhone == null) {
+              android.util.EventLog.writeEvent(0x534e4554, "79995313", -1, "");
+            }
+            Log.i(TAG, "ECMModeExitDialog launched - isInEcm: false" + " phone:" + mPhone);
             finish();
             return;
         }