Lua API for pcall/call. When called, it takes the args provided,
constructs a CallArgs payload from them, creates a temporary
LuaClientNode actor and sends them to it using the ask pattern.
The raiseErrors arg marks the different behavior when a runtime Lua
error occurs via pcall/call - specifically whether a LuaError is
raised (as with call), or a message table containing the error is
returned (as with pcall).