Plugin action-effect support

[alisonjlai]

• Added a new action-effect type.
• Created useActionEffect hook to register an action effect with the provided effect ID.
• Added a listener that calls the effect upon receiving wb:plugin:action-effect:invoke from Slate.
• Updated README.

Corresponding PR on Slate: https://github.com/sigmacomputing/slate/pull/35490

How it will look like in custom plugin:

useEditorPanelConfig([{ type: 'action-effect', name: 'exampleEffect' }]);

useActionEffect(config.exampleEffect, triggerEffect);

function triggerEffect() {
 //...
}