Transactions that cannot be immediately executed still show execution parameters

[katspaugh]

Description

When you create a transaction that won't be executed immediately (e.g. because there are enqueued txns), we still display gas estimation in TX Review modals.
Obviously, there won't be any immediate gas costs if a tx isn't going to be executed right away.

Steps to reproduce

1. Create a tx
2. Uncheck the Execute Transaction checkbox
3. Observe the gas estimation still displayed

Another case:

1. Create a tx
2. Uncheck the Execute Transaction checkbox
3. Submit the tx but don't execute
4. Create another tx
5. On the review screen, it has gas estimation

[katspaugh]

Will be fixed in #3257.