Flint: Fix memory leak on property tree
Closes #2188 (closed)
Relative to !3006 (merged)
This MR fixes the last memory leak from Flint.
It was due to cyclic ref on QStandardItem
(which are not QObject and dont have parent). That it's why maybe it was not obvious to found.
Only tested with 500 scans. The gap, looks to be a normal behaviour, maybe due to memory reallocation of one of the packages.
There is maybe something still , we could do more tests next week.