Add an option to show zero counts on Issue statistics gadgets

Summary

Issue statistics gadgets, it will only show values if there are actually any issues associated with those values. It will not show possible values if there are zero issues associated. Let's say you have a field called 'Fruit' with 4 possible values : apple, banana, orange, grapes. Those gadgets will currently only show the first 3 rows below, not the last one. We need the last one to show , too. Same goes for columns, in a 2-dimensional gadget.
Fruit Count
Apple 1
Banana 5
Orange 3
Grapes 0

Suggestion

It would be useful to add an option to show all values regardless of whether they have issues associated.