Add an opacity transition to all components with opening/closing behavior for consistency.

[Elijbet]

Description

Add an opacity transition to all components with opening/closing behavior for consistency.

Acceptance Criteria

All components with an open/close UI transition with opacity.

Relevant Info

The wiring up of the open/close utility/pattern in issues #5056 #4689 #4975 requires a transition to hook on to.

Which Component

Every relevant component. These should have an open prop or a legacy alternate prop, eg calcite-tree item has expanded currently.

Example Use Case

No response