Merge pull request #4122 from nextcloud/getAccounts

use own getAccounts() instead of AccountManager from AndroidSDK

src/main/java/com/nextcloud/client/account/UserAccountManagerImpl.java

@@ -71,7 +71,7 @@ public class UserAccountManagerImpl implements UserAccountManager {
 
     @Override
     public void removeAllAccounts() {
-        for (Account account : accountManager.getAccounts()) {
+        for (Account account : getAccounts()) {
             accountManager.removeAccount(account, null, null);
         }
     }