Date pickers of the event creation form are not displayed

[mouhb]

OS : MAC OS Bigsure 11.1/Linux Ubuntu 18.04
XWiki version : Chrome 77.0.3865.90/Firefox/Chromium
Calendar application version : 2.9.3

Steps to reproduce :

• On the Calendar application home page click on the "Create new event" button
• Click on the START DATE or END DATE inputs and notice what happens

Expected results : A date picker is displayed to allow the user to pick a date
Actual results : No date picker is displayed and a javascript error is displayed on the browser console . see screenshot :