Can't access the DW from another tab when installing a flavor

Note : apparently this bug was also found by lucaa and slauriere on a 10.11.8 wiki.

Context :

• You are running a distribution wizard : you have chosen a flavor to install from the flavor picker, and you have started the installation of this flavor
• You suddenly loose your tab (navigator crash, pc crash, …)
• Going back on the wiki after the crash, you get on the flavor picker of the distribution wizard (not the flavor install step)
• If you happen to select the flavor that you want to install and click on the button "Install this flavor", you will get the attached screenshot : a flavor installation step that doesn't show any progress and is stuck in this state until the wiki is restarted

How to reproduce :

• Start an upgrade of a wiki in 11.3.2
• During the installation of the flavor, kill the tab you are in
• Go back on the wiki
• Observe that you don't get at the same step of the DW as you were before (you should be on the flavor picker page)
• Select the flavor that you were installing and click on "Install this flavor"
• Observe that you arrive on an invalid installation step

Note : this bug won't show up if you reload the current tab

Other note : lucaa and slauriere also tried to reproduce that bug, and it seems that in some cases, you can get back to the non-stuck flavor installation step, especially if the installation was stuck on a conflict.