Add automated test for "Reset panels configuration"

The manual test is here: Reset panels configuration

The test verifies if reset panels configuration feature from Administer Wiki works properly.

What is missing from the automated test that already exists is:

• testing layout reset (Step 5 from the manual test)
• testing the reset after altering the values from "Panels displayed on the right" or "Panels displayed on the left" (Step 3 from the manual test)

Matrix discussion: https://matrix.to/#/!ikPtGZaGWtyblizzlR:matrix.xwiki.com/$1712056672666qIVIp:matrix.xwiki.com?via=matrix.org&via=matrix.xwiki.com&via=helsinki-systems.de

Vincent Massol: checking
Ilie Andriuta: BTW the test is not currently working IMO
Every time the 'Reset' button is clicked, the panels configuration is reverted (changes are undone, unless the page is saved).

^^ this is not working

Ilie Andriuta: checking on 15.10.8

Vincent Massol: wait I'll explain
for ex on playground we have for the list of panels on the left: Help.TipsPanel.WebHome,Panels.MyRecentModifications,Help.SupportPanel.WebHome,XWiki.CloudTryXWikiProPanel.WebHome
if I click reset I get: Help.TipsPanel.WebHome,Panels.MyRecentModifications
so it removes the saved settings

Ilie Andriuta: yes, it's expected
it's not a reset to factory

[...]

Vincent Massol: the reset button doesn't do factory reset (just checked the code)
it's supposed to save the values before changes and then to put them back
but apparently there's a bug (I"m debugging quickly to see if I can see the problem)

Ilie Andriuta: but then the behavior is weird on https://www.xwikiplayground.org/
resetting to other values before making any modification

Ilie Andriuta: on my 15.10.8, the test https://test.xwiki.org/xwiki/bin/view/Administration%20Tests/Reset%20panels%20configuration passes, the values/modifications are reset to the last values/modifications saved on Steps 3, 5 and 8

Vincent Massol: Reset doesn't reset to the saved values. its algorithm is faulty
anyway, stopping now, and checking the tests
I'll let you report what you want to in jira

Vincent Massol: Ilie Andriuta
"maybe because A.B are not real panels?"
you can try with real panels but it won't change anything
Regarding automated tests, we don't test the reset button
ah wait
we do

Ilie Andriuta: I found it on https://github.com/xwiki/xwiki-platform/blob/f19bd6fa13aee6600432e171409dd8570486f339/xwiki-platform-core/xwiki-platform-panels/xwiki-platform-panels-test/xwiki-platform-panels-test-docker/src/test/it/org/xwiki/panels/test/ui/docker/PanelsAdministrationIT.java#L53 from what I could see

Vincent Massol: we verify that if you drag and drop a panel and then click reset, it's removed
see https://github.com/xwiki/xwiki-platform/blob/23bb147f64947c5d50bd1dd2a352019679340362/xwiki-platform-core/xwiki-platform-panels/xwiki-platform-panels-test/xwiki-platform-panels-test-docker/src/test/it/org/xwiki/panels/test/ui/docker/PanelsAdministrationIT.java#L118

Ilie Andriuta: ok...

Vincent Massol: in the code the quicklinks panel is added to the left panel column and then reset and we verify it's been removed
we don't verify the reset of the list of left and right panels

Ilie Andriuta: there are 2 more use-cases, the Step 5 (layout) and Step 3 (altering the value of the panels)
ok...

Vincent Massol: yes

Ilie Andriuta: so I will create a task for it and mention the 2 tests we lack
and then report the bug from above
thank you, Vincent!