Log when save UI is not showing because of the service's response.

Bug: 74553423
Test: manual verification

Change-Id: I2ed43866b8384de2edea1a12e3da6adae2292c29
diff --git a/services/autofill/java/com/android/server/autofill/Session.java b/services/autofill/java/com/android/server/autofill/Session.java
index e14584f..e20c180 100644
--- a/services/autofill/java/com/android/server/autofill/Session.java
+++ b/services/autofill/java/com/android/server/autofill/Session.java
@@ -1400,6 +1400,7 @@
          *   the current values of all fields in the screen.
          */
         if (saveInfo == null) {
+            if (sVerbose) Slog.w(TAG, "showSaveLocked(): no saveInfo from service");
             return true;
         }