Update module-accounts close_account to remove proxies as well

[xlc]

It was not possible to call close_account for proxy created via module-nft because close_account requires no other reserved token and proxy is the only way to call close_account which means it will have reserved token.

The solution is to make close_account remove all the proxies first and then attempt to close the account.

Before paritytech/substrate#7557 is ready, we can just do this to remove proxies

let (_, proxy_deposit) = pallet_proxy::Proxies::<T>::take(&class_info.owner);
<T as pallet_proxy::Trait>::Currency::unreserve(&class_info.owner, proxy_deposit);

[xlc]

No longer needed after #566