TDI-31282 TBD-1204 fix bug: when there is a jar downloading action while
checking connection, the cancel progress dialog with time limit can not
work well
https://jira.talendforge.org/browse/TDI-31282
https://jira.talendforge.org/browse/TBD-1204

Now, change the time of cancel progress dialog to endless.
Merge branch 'maintenance/5.6'