bug(mat-expansion): focus on click & touch

[RobinKamps]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

Please add focus indication to mat-expansion header on click & touch.
it works with keyboard - but if it is used with a click the focus is not indicated.

Reproduction

Steps to reproduce:

1. https://material.angular.dev/components/expansion/overview
2. click or touch on the expansions headers to open (hover works, but focus / active is not persistent/indicated)
3. use tab / focus with keyboard (focus and active will be indicated)

it would be nice if you can add a ripple effect on click/action as well.

Expected Behavior

focus/active should be shown on click & touch

ripple effect on action

Actual Behavior

focus/active is not set/shown (it is shown with keyboard navigation)

no ripple

Environment

• Angular: latest 20x
• CDK/Material: 20.0.2
• Browser(s):
• Operating System (e.g. Windows, macOS, Ubuntu):