Fix getEarliestCreatedFullUser initial value

If user 0 isn't a full admin, its creation time should not be part of the calculation.
Currently, user 0 will generally be the earliest created user, so no other user can get returned (even if user 0 isn't a full user).
This fixes the bug.

Bug: 256624031
Change-Id: Idee2d5957560dd8556c53f85645981816494acc6
Test: local
diff --git a/services/core/java/com/android/server/pm/UserManagerService.java b/services/core/java/com/android/server/pm/UserManagerService.java
index 88e12fa..23a6b67 100644
--- a/services/core/java/com/android/server/pm/UserManagerService.java
+++ b/services/core/java/com/android/server/pm/UserManagerService.java
@@ -3783,10 +3783,10 @@
     private UserInfo getEarliestCreatedFullUser() {
         final List<UserInfo> users = getUsersInternal(true, true, true);
         UserInfo earliestUser = users.get(0);
-        long earliestCreationTime = earliestUser.creationTime;
+        long earliestCreationTime = Long.MAX_VALUE;
         for (int i = 0; i < users.size(); i++) {
             final UserInfo info = users.get(i);
-            if (info.isFull() && info.isAdmin() && info.creationTime > 0
+            if (info.isFull() && info.isAdmin() && info.creationTime >= 0
                     && info.creationTime < earliestCreationTime) {
                 earliestCreationTime = info.creationTime;
                 earliestUser = info;