Add option for websocket message size limit

[Tristan-Wilson]

closes NIT-2449

This plumbs through the websocket message size limit option for all rpc clients.

Testing done

Checked that this option is present for all clients and that the default is correctly set.

$ make target/bin/nitro
go build  -o target/bin/nitro "/home/tristan/offchain/nitro/cmd/nitro"
$ ./target/bin/nitro --help 2>&1 | grep websocket-message
      --node.block-validator.execution-server-config.websocket-message-size-limit int                          websocket message size limit used by the RPC client. 0 means no limit (default 33554432)
      --node.block-validator.validation-server.websocket-message-size-limit int                                websocket message size limit used by the RPC client. 0 means no limit (default 33554432)
      --parent-chain.connection.websocket-message-size-limit int                                               websocket message size limit used by the RPC client. 0 means no limit (default 33554432)

[PlasmaPower]

Let's increase this to 256 MiB (for the other websocket clients as well). All of these websocket clients are expecting the server to be honest.

[tsahee]

let's test here if WebsocketMessageSizeLimit == 0 (it can happen e.g. for validation-server-configs). If it's 0 either use default or don't apply rpc.WithWebsocketMessageSizeLimit

[Tristan-Wilson]

0 will use default https://github.com/OffchainLabs/go-ethereum/blob/master/rpc/websocket.go#L254

(see also
https://github.com/OffchainLabs/go-ethereum/blob/master/rpc/client.go#L216
https://github.com/OffchainLabs/go-ethereum/blob/master/rpc/client_opt.go#L72)

[tsahee]

LGTM