[CardPreference] Set the trailing icon to not be clickable if its action is null.

This is for cases where the icon should be visible but doesn't need a separate action from the rest of the card. To have it be separately clickable is confusing for a11y purposes.

Bug: 435035588
Flag: EXEMPT library
Test: manual
Change-Id: Id17489d5a57462ee1a4e957c1e1bab412edbc05c