Sub graphs that include the Linear Blend Skinning Node will display an error stating "invalid subscript 'BoneIndices'. Which will prevent your shadergraph from compiling properly.

Repro Steps:
1. Launch Unity Editor Version 2019.3.4f1 (4f139db2fdbd) with Shadergraph Version 7.3.0
2. Create a new PBR Graph
3. Create a Linear Blend Skinning Node
4. Connect the outputs to your master node
5. Highlight the Linear Blend Skinning Node, right click -> Convert to sub-graph
6. Observe the error reported by the sub-graph

Actual Results:
This node will report an error stating "invalid subscript 'BoneIndices'" and will prevent the shadergraph from compiling

Expected Results:
no error would occur and this node would be able to be used within a Sub-Graph