wallet-http: create account: remove unused 'watch-only'

When a new account is created, it inherits its `watch-only`ness from the wallet that contains it. By removing this check, user will get "unrecognized option" error if they try to create an account with `watch-only`. Otherwise the parameter is just ignored and could cause user confusion.

lib/wallet/http.js

@@ -324,7 +324,6 @@ class HTTP extends Server {
       const options = {
         name: valid.str('account'),
         witness: valid.bool('witness'),
-        watchOnly: valid.bool('watchOnly'),
         type: valid.str('type'),
         m: valid.u32('m'),
         n: valid.u32('n'),