JSON-RPC should not require "jsonrpc" "2.0" in deprecated mode yet.

[rustyrussell]

#5657 (comment)

Apparently BTCPayServer still wants this, so removal is premature.

[vincenzopalazzo]

Can someone point me to this in the BTCPayServer code where the call to cln wrapped happens? I think this required less than 2 line of code to fix it, maybe we can avoid reverting it?

cc @NicolasDorier

[NicolasDorier]

#5783 (comment)