UI: Stake is disabled if user is already staked in pool, but the pool is currently full of stakers.

A user reported that they already have stake in a particular pool and stopped being able to 'add' more stake to the pool using the stake button. The pool is full (200 of 200 stakers) but the user should still be able to add more stake. The UI needs to account for this in its enabled/disabled logic on the 'my stake' lists' stake button.