Prevent apps from spamming addAccountExplicitly.

See comment here for the discussion on solution
https://b.corp.google.com/issues/169762606#comment14

Change-Id: If212df3a3b7be1de0fb26b8e88b2fcbb8077c253

Bug: 169762606
(cherry picked from commit 11053c17b3)

Change-Id: I424e098dd70ae31bbbc7cb2f3eccd1ccc287064b
Merged-In: If212df3a3b7be1de0fb26b8e88b2fcbb8077c253

services/core/java/com/android/server/accounts/AccountManagerService.java

@@ -1788,8 +1788,8 @@ public class AccountManagerService
                         return false;
                     }
                     if (accounts.accountsDb.findAllDeAccounts().size() > 100) {
-                        Log.w(TAG, "insertAccountIntoDatabase: " + account
-                                + ", skipping since more than 50 accounts on device exist");
+                        Log.w(TAG, "insertAccountIntoDatabase: " + account.toSafeString()
+                                + ", skipping since more than 100 accounts on device exist");
                         return false;
                     }
                     long accountId = accounts.accountsDb.insertCeAccount(account, password);