Bubble v2 a11y.

- Set checkable for bubble buttons so the check status of non checkable button (back to call, end call) is not read.
- Add support for bottom action buttons.

Test: manual
PiperOrigin-RevId: 183150371
Change-Id: Ifae9c912ec923e8d2cda3146413138bd2eb94b47
diff --git a/java/com/android/newbubble/NewBubble.java b/java/com/android/newbubble/NewBubble.java
index 8b188ba..2e98ad1 100644
--- a/java/com/android/newbubble/NewBubble.java
+++ b/java/com/android/newbubble/NewBubble.java
@@ -722,7 +722,7 @@
       button.setCompoundDrawablesWithIntrinsicBounds(action.getIconDrawable(), null, null, null);
     }
     button.setChecked(action.isChecked());
-    button.setEnabled(action.isEnabled());
+    button.setCheckable(action.isCheckable());
     button.setText(action.getName());
     button.setContentDescription(action.getName());
     button.setOnClickListener(v -> doAction(action));