Interface cast nodes can be placed for non-object pins

Interface Cast nodes appear to be returned as valid and context sensitive for every possible pin, even ones like floats and integers. Following the repro above, it is easy to place a node but it will never compile. These cast nodes pollute the global namespace and make it harder to find valid function calls

Interface cast nodes should only show up for Object and Wildcard pin types. CustomStructureParam seems to cause the same issue, but that might be unrelated

1. Load up any blueprint
2. Place a Make Literal Float node
3. Drag off right side of node, type cast, note that many Cast To (Interface name) nodes are incorrectly listed
4. Select one of the nodes, it will place it and hook up the float. But if you try to compile it will fail