With each click on the "Check connection" button the "Test connection" message multiplies

[ane-gabriela]

Steps to reproduce:

1. Connect to the AD (follow the steps from Test Connection
2. In Administer Wiki > Other > Active Directory make sure you added valid AD credentials
3. Click on the Check connection button
4. Click on Check connection again

Expected results: "Test connection succeeded!" appears.

Actual results: Witch each click of the button a new "Test connection succeeded!" info message appears.

Environment: Windows 10, XWiki 11.10.4 with MySQL 5.7 and Chrome 80, Active Directory Application 1.8.1