(impact: low) Add missing unit tests for action menu component

[ps37]

Prerequisites

[Check these off before submitting an issue].

• Are you running the latest version?
• Did you perform a basic issue search?

Description

Add the following missing unit tests to the action menu component:

• Test actions with availability as observable are in fact being hidden/shown based on the updates from the observable stream
• Test actions with availability as boolean or function are in fact being hidden/shown based on the values of action.availability

Impact

Test coverage of logic that is changed.