Disable multiuser toggle om COPE device and add explanation dialog

Bug: 304359233
Test: set up device in COPE mode and check toggle in Settings -> System -> Multiple Users

Change-Id: I0edd58651f94c9f9a51349025a29e33a1e1a9c14
diff --git a/src/com/android/settings/users/MultiUserSwitchBarController.java b/src/com/android/settings/users/MultiUserSwitchBarController.java
index 33651c3..238e86e 100644
--- a/src/com/android/settings/users/MultiUserSwitchBarController.java
+++ b/src/com/android/settings/users/MultiUserSwitchBarController.java
@@ -57,11 +57,10 @@
             mSwitchBar.setDisabledByAdmin(RestrictedLockUtilsInternal
                     .checkIfRestrictionEnforced(mContext, UserManager.DISALLOW_USER_SWITCH,
                             UserHandle.myUserId()));
-
         } else if (mUserCapabilities.mDisallowAddUser) {
+            onSwitchToggled(false);
             mSwitchBar.setDisabledByAdmin(RestrictedLockUtilsInternal
-                    .checkIfRestrictionEnforced(mContext, UserManager.DISALLOW_ADD_USER,
-                            UserHandle.myUserId()));
+                    .checkIfAddUserDisallowed(mContext, UserHandle.myUserId()));
         } else {
             mSwitchBar.setEnabled(!mUserCapabilities.mDisallowSwitchUser
                     && !mUserCapabilities.mIsGuest && mUserCapabilities.isAdmin());