Ability added for to show the custom Icons on Expansion of node.

[rajputvarun591]

Description

Ability added for user to add custom icons in place of the default icons. if no icons will specified then the default icons will be there. added properties primaryIcon for when Node will be in Unexpanded state and secondaryIcon for when Node comes in expanded state.

TODO

Related Issues

TODO

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[jamesderlin]

Why do you keep opening new PRs and then closing them? Please stop that.

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