Add Sub Board names in Repeter node details

[itsjorgebar]

Expected Behavior

When assigning a worker Sub Board to a Repeater node, the board names are listed.

Actual Behavior

An encoded string represents the Sub Boards, which makes it difficult to identify them.

Steps to Reproduce the Problem

1. Open the visual editor
2. Create a Sub Board named "foo".
3. Go back to the Main Board.
4. Create a Repeater node.
5. Click the Repeater node.
6. Click the Worker dropdown to select a worker.
7. Notice there is no Sub Board named "foo"

[dglazkov]

Good bug.