Warnings in the XWiki console once the trial license is selected

[ane-gabriela]

Steps to reproduce:

1. Click on Administer Wiki
2. Click on Extensions > Extensions
3. Search for Google Apps Integration (Pro)
4. Click on Install and Continue
5. Get trial license from Administration
6. Observe the messages from the XWiki console

Expected results: The trial license is added with no warnings.

Actual results: Warnings appear in the XWiki console

`Nov 19, 2020 2:09:44 PM com.google.javascript.jscomp.LoggerErrorManager println
WARNING: xwiki:GoogleApps.JSExtension:17:5: WARNING - [JSC_DELETE_VARIABLE] variables, functions, and arguments cannot be deleted in strict mode
17| delete listener;
^^^^^^^^^^^^^^^

Nov 19, 2020 2:09:44 PM com.google.javascript.jscomp.LoggerErrorManager printSummary
WARNING: 0 error(s), 1 warning(s)
2020-11-19 14:09:44,165 [qtp668849042-629 - http://localhost:8080/xwiki/bin/jsx/GoogleApps/JSExtension?language=en&docVersion=1.1] WARN c.x.x.w.s.JsExtension - Warning at line [17], column [5]: [variables, functions, and arguments cannot be deleted in strict mode]`

Environment: Windows 10, XWiki 12.9 Standard and MySQL 8.0, IE 11, Google Apps Integration (Pro) 2.4.7