fix(line-chart): improved paint order
fix(line-chart): improved paint order

and touch indicator always on top using srcOver

imaNNeoFighT/fl_chart,imaNNeoFighT/fl_chart,imaNNeoFighT/fl_chart,imaNNeoFighT/fl_chart,imaNNeoFighT/fl_chart,imaNNeoFighT/fl_chart,imaNNeoFighT/fl_chart