Allow binding keys to a nested action, to open the palette directly to it's children

the problem:

currently every time i go change the colour scheme of my profile because i walk into an area with different lighting and need different contrast, i have to laboriously click the colour scheme dropdown, select my scheme i want to try, then drag my mouse over to the apply button, then switch tabs back to that profile to see if it suits my lighting, which it might not, in which case i have to go do that process again.

naturally it would be nice to use keyboard shortcuts for most of this:
1: ctrl+shift+tab to switch between settings and my terminal window
2: mouse is already over the dropdown, click to enter dropdown
3: use arrow keys to select colour profile, enter
4: >>>>press enter to apply<<<<
5: ctrl+shift+tab to switch back and check the colour scheme works

having it that way wouldnt require me to move my mouse at all, very convenient.

simple solution:
pressing enter applies changes in settings menu

Description of the new feature/enhancement

Proposed technical implementation details (optional)

Start by tracing the settings menu's colour-scheme dropdown, apply button, and the nested-action/key-binding entry points mentioned in the issue. Confirm how keyboard focus and Enter are handled, then verify that a binding can open the palette to its children and that Enter applies the selected scheme without mouse movement.