Row index is repeated if object is an element in the list more than once

[kraenhansen]

The index of an object is determined by asking the list what the index of the object is - if it's in the list twice, this will only return the first index.

This happens due to https://github.com/realm/realm-studio/blob/master/src/ui/RealmBrowser/Content/Table/index.tsx#L210.

Solving this might be a little tricky if we want to display the original index in the list while the user sorting in a column.