Update spacing and alignment of smart action buttons

This ensures that the buttons are up to spec:
- icons are 20x20dp
- inner vertical padding is 8dp
- inner horizontal padding is 12dp
- text is left-aligned when two-line

It affects all types of related chips: smart actions, smart replies,
animated actions and animated replies.

Fix: 427242450
Test: screenshot tests + manual
Flag: android.app.notifications_redesign_templates
Flag: com.android.systemui.notification_animated_actions_treatment
Change-Id: I132c2805eeb2513be0ea247fcb105d00828c7848