Pressing back when the dialpad is empty now exist the search UI.

Bug: 65687672
Test: existing
PiperOrigin-RevId: 168951800
Change-Id: Ie840acd608424551198ba3440d6060a7cd7a629f
diff --git a/java/com/android/dialer/app/DialtactsActivity.java b/java/com/android/dialer/app/DialtactsActivity.java
index 0b2f375..588f9d7 100644
--- a/java/com/android/dialer/app/DialtactsActivity.java
+++ b/java/com/android/dialer/app/DialtactsActivity.java
@@ -1291,6 +1291,9 @@
     }
     if (mIsDialpadShown) {
       hideDialpadFragment(true, false);
+      if (TextUtils.isEmpty(mDialpadQuery)) {
+        exitSearchUi();
+      }
     } else if (isInSearchUi()) {
       if (mIsKeyboardOpen) {
         DialerUtils.hideInputMethod(mParentLayout);