Actions: Perform client side validation

[SchoolGuy]

Is your feature request related to a problem? Please describe.

As a user
I want to be warned of invalid inputs as early as possible
so that can be certain that when I trigger an action that it is executed successfully.

Describe the solution you'd like

Implement reasonable client-side validation on the given user inputs. At minimum, there are required fields that are probably not marked as such.

Describe alternatives you've considered

None

Additional context

This is essentially an EPIC for issues like #381 and #382. There are many more fields that can be validated client-side.