Fix non-typed Dictionary keys displayed as <null> in the inspector.

[bruvzg]

Fixes #101272, regression from #100512

[Sauermann]

I can confirm, that this change resolves the <null> display problem for me.

Before #100512, the content of Array keys were directly visible (however in numeric form).
With this change, I need to click on each individual array element, to see its value, which seems to me like an inconvenient usability change. So finding a specific key now requires in the worst case a mouse-click on every key:

I'm not entirely sure, what should be considered a higher priority:

• Easy access to Array keys
• Visual representation of every Enum/Color/... key

[bruvzg]

I'm not entirely sure, what should be considered a higher priority:
Easy access to Array keys
Visual representation of every Enum/Color/... key

Not sure. Old mode (showing conductor string as label) was only usable with simple and small arrays, and it's still available as tooltip.

[Sauermann]

and it's still available as tooltip

For me on Linux X11 with Editor Single Window Mode off, I don't get tooltips when hovering over the Array (size x) Dictionary key nodes.

[bruvzg]

Added #101331 code, but only applied to keys, so it should not change current value display and restore contents info for keys.

[akien-mga]

Thanks!