aotf: access "see more" menu on scroll

[Oliver Sanders]

An interesting suggestion made in #1364.

To make the Cylc UI easier to navigate and use we only display the most commonly used commands (aka GraphQL mutations) in the command menu. This also helps to reduce the learning curve / new user bounce when picking up Cylc. To access the full list, there is a "see more" button.

The suggestion is to allow scrolling as an alternative to clicking the "see more" button as a more convenient pathway for power users.

Investigation:

If this is something we can easily achieve with Vuetify, it's worth a shot, otherwise consider a keyboard shortcut.