Cannot insert value in Dictionary in visual script

[JordanMotta]

Operating system or device, Godot version, GPU Model and driver (if graphics related):
Debian 9, Godot v3.0.alpha.custom_build.2fce001

Issue description:
I cannot insert values in a dictionary in visual script. I have a variable called "bar" which is dictionary type, but when i open the variable properties, the section "Value" doesn't let me insert anything. So i decided to grab and place "foo" on the grid keeping the control button pressed and it doesn't work neither. I guess this is the right way to assign a value because a variable of an Array type i can do it in this way. Sorry the English.

Steps to reproduce:

1. Create a project.
2. Add a root node.
3. attach it to a visual script
4. make a function or override someone.
5. create a new variable of type Dictionary
6. Try to insert a value

Link to minimal example project:
dictionary.zip

[bojidar-bg]

Likely related to the lack of a Dictionary editor, refs #12015.

[27thLiz]

#11940 implemented a dictionary editor, but it doesn't seem to work with VisualScript.
CC @Geequlim

[akien-mga]

Not critical for the upcoming 3.0 release, so moving to the next milestone. A fix can still be cherry-picked for 3.0.x maintenance releases once available in the master branch.

[reduz]

This is fixed now, given new inspector.