Fix --add-profile flag

[kkawula]

Which components does the task require to be changed? (think hard pls)

sncast

Description

When calling

sncast \
    account create \ 
    --add-profile profile1
    --url http://127.0.0.1:5050 \
    --name some-name

Generated is entry in snfoundry.toml with blank url field

[sncast.profile1]
account = "some-name"
accounts-file = "/path/to/starknet_open_zeppelin_accounts.json"
url = ""