Witness_node: Feeding private key through option "private-key" is not allowing during witness node start up.

Below are the comments from one of the witness.

Error parsing command line: option '--private-key=["TEST8PUiCmU57PkyF22Qpzc1z2V8EyADafF6FLQP72nZ66BEzpQFtr","privatekey"]' is ambiguous and matches different versions of '--private-key'