Multisig creation - default to min 2 keys and validate the required sigs

[monikasmolarek]

Currently, the multisig account creation process allows one to create the account with only 1 signature and with more required signatures than the designated parties.

For a multisig account creation, we should have the default displayed as 2 and field validation for a minimum of 2 keys, not letting the user input less than 2, but also not more than added parties. Here I was able to set "Required amount of signatures" as 6 while indicating only 2 keys as signers.